Considering the Role of Language Input in Congenital Deafblind Children
ABSTRACT
In the field of congenital deafblindness, communication and language support is one of the most important and more developed areas of research (Bruce, Nelson, Perez, Stutzman, & Barnhill, 2016). Despite the interventions offered, it appears most deafblind children do not make the transition to symbolic communication. An important question related to the language acquisition of these children is why some children with congenital deafblindness develop more communication skills and higher levels of communication than others. The suggested explanations alone cannot seem to explain their language development, which in turn suggests that their language development is at least part dependent on other factors. The present explorative paper addresses this question by considering language input as an important part of the sociolinguistic environment, as a factor that may influence the acquisition of language. The language input and output of one congenitally deafblind child in the interaction with his communication is explored to describe his sociolinguistic environment, in which language acquisition takes place. The results of the present paper have revealed that the input was reflected in several areas of the output. Consequently, language input may be an important factor to consider in the language acquisition of deafblind children. Most interventions offered to deafblind children nowadays supports their early social interaction and communication. The findings of the present paper may be important to consider for the development of interventions that can lead to the development of symbolic language in the case of deafblindness.
Masterthesis Neurolinguistics
University of Groningen, Faculty of Arts Author: Soraya Visser (2314819) Supervisor: dr. G. W. Bol
Children with congenital deafblindness (CDB) are both deaf and blind from birth. This definition suggests that it may be easy to define deafblindness and to identify children with deafblindness. In reality, there is considerable variability within this group of children with regard to the degree of vision and hearing loss. Most individuals with congenital deafblindness are not entirely deaf and blind, but have to some degree, and make to some extent use of, vision and hearing (Ask Larsen & Dammeyer, 2015; Bruce et al., 2016; Dammeyer, 2012). Regardless of the degree of vision and hearing of some deafblind children, the combination of both vision and hearing impairments presents a distinct disability. Thus, it is the combination of hearing and vision impairments that result in deafblindness (Dammeyer, 2012). Furthermore, congenital deafblindness refers to individuals who are either born deaf and blind or become deaf and blind before the development of language (Dammeyer, 2011). In contrast, acquired deafblindness refers to those individuals who become deaf and blind after the development of language.
The effect of deafblindness cannot be understood by simply adding up the effects of visual and hearing loss, because vision and hearing are the two distant senses people rely on most as they learn and develop (Bruce et al., 2016). These distant senses allow the mind to acquire and access information from the environment without making direct contact with objects and entities within that environment (Deasy & Lyddy, 2009). Moreover, these two senses play a crucial role in language acquisition. As a consequence, children with congenital deafblindness face serious difficulties, with the most important one related to language development, and thus communication
be described for several language situations in paragraph four. Next, the research questions will be formulated followed by a description of the design of the present paper. Since little is known about the sociolinguistic environment of congenitally deafblind children, the first aim is to describe the sociolinguistic environment of one deafblind boy, namely Tom. The second aim is to explore the role of language input in the atypical language situation of deafblind children.
1.1: Supporting the Early Communication Development of Children with Congenital
Deafblindness
1.1.1 Theoretical Background
Although the development of language and communication has been a central theme in the field of deafblindness, the educational focus has changed over time. During the last two decades, the focus has been on supporting early social interaction and communication (Ask Larsen, 2013; Ask Larsen & Dammeyer, 2015; 2016, Damen, Janssen, Huisman, Wied, Ruijssenaars & Schuengel, 2014; Damen, Janssen, Wied, Ruijssenaars & Schuengel, 2015a; 2015b). Inspiration was taken from the social interaction theory of early language development, which proposes that social interaction between a child and an adult are fundamental for the development of symbolic language development (Dammeyer et al., 2015; Damen, 2015c). Following this view, early social interactions are a fundamental precondition for language development (Ask Larsen, 2013). At a very early age, infants begin to develop and acquire language through social interactions with other people. As Damen (2015c) has stated, “it is through these social interactions that infants begin to grasp and understand the relationship between signs and symbols, what signs and symbols represent, and how language is used to achieve desired goals” (p. 11).
practice communication and imitate the language use of others (Bruce, 2005; Cascella, Bruce, & Trief, 2015). As a result, these children need support in order to understand the world around them. Moreover, deafblind children are in need of an environment that enables communication between the congenitally deafblind child and a communication partner (Villas Boas, De Moura, Rodrigues Maia, Amaral, & Piccolotte Ferreira, 2016). If expressions and turn taking processes are not grasped and understood by the communication partner, this can lead to mutual misunderstanding and difficulties in the early communication development. Ultimately, delays in the early social interaction can for some children mean that they will never achieve symbolic understanding and expressions (Bruce, 2005; Bruce & Vargas, 2007).
1.1.2 The Early Communication Development of Congenital Deafblind Children
In the literature, it is often reported that very few children with congenital deafblindness achieve symbolic language (Ask Larsen, 2013; Damen, 2015c; Cascella et al., 2015). Moreover, research has repeatedly shown that most deafblind children primarily use pre-linguistic communication in their communication with others (Bruce, 2005; Bruce & Vargas, 2007; Cascella et al., 2015; Damen et al., 2014; Janssen, Riksen-Walraven, & van Dijk, Jan P M, 2002; Janssen et al., 2014; Villas Boas et al., 2016). Since these problems are understood as the consequence of problems in the early social interaction, most research to date has focused on creating and expanding early social interactions, which are seen as fundamental for the development of (symbolic) communication.
In the context of understanding the development to symbolic language, specific developmental markers in the early social interaction related to language development have been described in depth. These specific developmental markers are important milestones in the normal development of communication, and are used as a frame of reference when describing the early communication development of congenitally deafblind children. Examples of these developmental markers are turn taking, intentional behaviour and joint attention. Turn taking, intentional behaviour and joint attention have furthermore been identified as predictors for the achievement of symbolic language (Bruce, 2005; Bruce & Vargas, 2007; Dammeyer, 2012; Villas Boas et al., 2016). It has been suggested that these milestones are especially relevant to examine in children with congenital deafblindness, because these milestones are generally achieved in the context of experiences that are shared by communication partners (Bruce, 2005; Bruce & Vargas, 2007).
develops an understanding that behaviours have consequences and that these behaviours influences adults (p. 329)”. The achievement of joint attention in the case of deafblindness is particularly vulnerable, since these children cannot achieve it on their own. It is therefore important to understand and act upon the complexity deafblind children deal with in achieving, for example, joint attention. In the case of deafblindness, it is through direct contact with objects and entities they can have access to information from the world around them. As a result, they are in need of a communication partner who can inform them of the presence and actions of others. Furthermore, the use of tactile strategies has reported to be of great significance to support the development of joint attention (Brede & Souriau, 2016; Bruce & Vargas, 2007; Dammeyer et al., 2015; Villas Boas et al., 2016).
In the context of supporting language development, the communicative competence of the communication partner is believed to be of great importance in the development of early social interactions of congenitally deafblind children (Janssen et al, 2006; Damen 2005). From an intersubjective developmental perspective, Damen et al. (2015a) stated “the treatment of communication problems should focus on partner strategies and on creating opportunities for social interactions, rather than on training a child in individual language skills” (p. 238). Because the communication problems of congenitally deafblind children are here understood as related to problems in social interaction between these children and their communication problems, the interventions have mainly focused on the communication skills of the communication partner. The partner strategies have specific purposes and can be used to develop meaningful social interaction with congenitally deafblind children. For example, one partner strategy that has been proposed has focused on attunement to the emotions and behaviours of congenitally deafblind individuals. In this intervention, communication partners were trained to better attune to the communication needs and abilities of individuals with congenital deafblindness (Damen et al., 2014; Damen et al., 2015a; 2015b). The communication partners were supported to respond bodily to the child’s expressions, because other communication forms are inaccessible to the child. As a result of these adaptions, more meaningful social interactions occurred in the interaction with congenitally deafblind individuals.
1.1.3 Conclusion
means for later language development (Bruce 2005; Damen et al., 2014; Damen et al., 2015a; 2015b). As stated by Dammeyer et al. (2015), “the support to congenital deafblind children’s social interaction and communication development has offered many children the first crucial step from isolation and deprivation” (p. 2). Despite this, the help offered nowadays has overlooked the need for support to early stages in language development, while this is characterized as severe. In a similar way, the importance of describing the symbolic language development of congenitally deafblind children is that it may contribute to our understanding of the communication problems of these children at the symbolic level. This in turn may lead to the development of interventions for supporting the language acquisition and the later language development of congenitally deafblind children.
1.2: The Communication and Language Development of Children with Congenital
Deafblindness
1.2.1: Theoretical Background
Dammeyer et al. (2015) has argued that the support of early social interaction by using the tactile modality as a means for later language development is the dominating rehabilitation approach in congenital deafblind education today. A consequence of the focus on early communication development is that little research has focused on describing the development of symbolic communication and language abilities of this group of children (Ask Larsen, 2013; 2016; Ask Larsen & Dammeyer, 2015; 2016). During the last decade, a few studies have been published that have focused on the (symbolic) language development and language abilities of congenitally deafblind children. These studies have mostly aimed at describing the congenitally deafblind population in terms of their communication development and language abilities. The next paragraph will present the existing literature on the communication development and language abilities of congenitally deafblind children.
1.2.2 Communication and Language Abilities of Congenitally Deafblind Children
communication was also reported, of which the latter appeared to be the most frequently used communication mode. In addition, the use of idiosyncratic signs, gestures, or behaviours have been identified by Dalby et al. (2009) as the most common communication modes of congenitally deafblind adults. Both studies have demonstrated that many individuals with deafblindness are not restricted to one mode, but that most participating individuals made use of more than one mode of communication (Dalby et al., 2009; Dammeyer & Ask Larsen, 2016). The overall picture that emerges from these results is that the group is heterogeneous with regard to communication mode used and the level of language acquisition they achieve.
With regard to the level of language acquisition, Dammeyer and Ask Larsen (2016) reported that most children used pre-verbal communication modes, which included social interaction and gestures. Of the 71 children included in this study, only twelve children used conventional sentences (Dammeyer & Ask Larsen 2016). These results support the idea that some children with congenital deafblindness achieve symbolic language, whereas most children remain at the pre-symbolic language level.
In addition, a few case studies of congenitally deafblind children have been published that have described the communication and language development of this group of children. For example, Deasy and Lyddy (2009) have described the emerging language capabilities of Amy, a young girl with congenital deafblindness. At the start of the study, it was reported that Amy had approximately twenty-five signs in her vocabulary. Furthermore, she used a combination of various types of sign systems, ranging from Irish Sign Language (ISL), adaptive signs and natural gestures. At home and in the school her intervention was based on teaching Amy LAMH signs, which is the manual sign system of Ireland. Observations were videotaped over a nine-month period and the transcripts were examined for communicative behaviours such as gestures, sign systems and the functions of behaviours were also identified. The authors concluded that the development of sign language was evident in the data.
In addition, Souriau et al. (2009) has described the communication development of Emil, an 8-years-old congenital deafblind boy. When Emil was two-years-8-years-old, it was reported that he was communicating with gestures, sounds, facial and bodily expressions. The parents of Emil learned tactile sign language, but the communication with Emil was a mixture of spoken language, sounds, signs, gestures and drama (Souriau et al., 2009). From age 3 years and 6 months, it was reported that Emil began to put signs together in small sentences and from age 4, it was reported that his communication developed further. More specifically, his signing developed quickly, which was shown by the fact that Emil began to sign longer sentences.
1.2.3 Conclusion
level of language acquisition, this has mostly been assessed in terms of absence or presence of symbolic communication. Although few studies have shown that some deafblind children achieve symbolic communication, no information regarding the level of language development and linguistic abilities of this group of children has been given. The few existing case studies that have reported the language abilities of deafblind children, have not properly described the communication and language development of these children. The only development reported for Amy was that three word sentences appeared within her signing. Although the use of three word sentences may reflect the emergence of grammar development, it is not possible from the study to tell whether these signs were signed visually or tactically. Furthermore, beyond the description that three signs were used to form a sentence, the grammatical complexity of the sentences was not reported. In a similar way, the development of Emil does not describe the actual communicative skills of this child. Even though the authors argued that Emil’s signing developed quickly, the only description of linguistic capacities given was in terms of the length of sentence. Again, it is not possible to tell whether the signs of Emil were signed visually or tactically. Thus, even in the case of case studies, not much is known about the actual language development and linguistic abilities of congenital deafblind children. In sum, throughout the literature, research on the symbolic communication development and language abilities of congenitally deafblind children is scarce. Of the few existing studies and case studies that have described the symbolic communication and language abilities of this group of children, not much information is given on either the symbolic communication development or the linguistic abilities of these children. Taken together, research has not yet provided a clear description and understanding of the (symbolic) language development in the case of deafblindness. This suggest that what is needed, are other ways of reporting on the language development of children with congenital deafblindness that focus on linguistic competence in order to describe and understand their (symbolic) language development and linguistic abilities.
1. 3: The Natural Language of Congenitally Deafblind Children
1.3.1: Theoretical Background
Several authors have proposed that congenitally deafblind children have to acquire language within the tactile modality, because that is their primarily communicative access to the world (Ask Larsen 2013; Bruce 2005; Bruce & Vargas 2007; Dammeyer et al., 2015; Villas Boas et al., 2016). Similar to the natural language development in the visual modality among deaf children, language may also develop naturally in the tactile modality among congenital deafblind children (Dammeyer et al., 2015). The importance of the tactile modality in relation to deafblindness has already been suggested in the literature on the early social interaction, where it was found that developmental milestones such as joint attention are usually achieved tactically. In addition, studies have repeatedly demonstrated that tactile expressions are most evident in the early communication of congenitally deafblind children (Brede & Souriau, 2016; Bruce, 2005; Bruce et al., 2016; Bruce & Vargas, 2007; Janssen et al., 2002; Janssen et al., 2014; Villas Boas et al., 2016). Even more importantly, several studies have demonstrated that symbolic communication is evident in the tactile modality (Dammeyer et al., 2015; Wolthuis 2013).
This in turn has led to the hypothesis that tactile languages are unique languages shaped by the tactile modality (Dammeyer et al., 2015). One case study has explored the potential tactile language structure in the areas of phonology, morphology, semantics and syntax (Dammeyer et al., 2015). This study has shown that structural language structures can be described in the tactile modality. For example, proposed building blocks of tactile phonology may include speed, position relative to other body parts and muscle tension.
1.3.2: The Linguistic Capacities of Congenitally Deafblind Children
With the potential of the tactile modality as the natural language for congenitally deafblind children, it is now possible to examine the linguistic capacities of congenitally deafblind children. Recently, the first known study appeared that assessed the linguistic abilities of a child with congenital deafblindness in linguistic terms (Wolthuis, 2013). This study has for the first time focused on the structural aspects of language, instead of symbolic aspects of language. Structural aspects were examined by analysing the phonological, lexical and morphosyntactic development of one congenitally deafblind child. The linguistic milestones for typically developing children have been used as a frame of reference for describing the language development and linguistic abilities of a congenitally deafblind child.
deafblind children to acquire some of the structural properties of language. In addition, the analysis of the language acquisition in the areas of phonology, lexicon and morphosyntac provided evidence that Tom’s linguistic milestones are more or less the same as those of typically developing children and children with a single sensory disability (children with blindness or deafness).
1.3.3: Conclusion
Recent research has for the first time described the linguistic capacities of congenitally deafblind children in linguistic terms, and has furthermore demonstrated that it is possible for congenitally deafblind children to acquire structural properties of language. These results indicate that the vision and hearing impairments of congenitally deafblind children alone, do not prevent the development of language. As Wolthuis (2013) argued, although it is possible for deafblind children to acquire language, there is still a lot to be learned from their language on a descriptive level as well as by explaining their linguistic development. It is still unclear why some children develop higher levels of language acquisition and more communication abilities than others.
From the social interaction perspective, it was hypothesized that early social interactions is a necessary precondition for language development. However, there are cases reported in which congenitally deafblind children do not develop language, even where the fundamental social development is in place (Ask Larsen, 2013). This suggests that good early social interactions alone, is not a sufficient condition for the acquisition of language. Dammeyer and Ask Larsen (2016) have proposed that the different degrees of hearing and vision impairment may affect both the communication mode used and level of language acquisition. Although it is clear that having a dual sensory impairment may negatively effect language development, another study found no correlation between the degree of sensory impairments and cognitive or communicative delay in the congenitally deafblind population (Ask Larsen, 2013). Moreover, the measurements of sensory impairment were not sufficient in predicting the language development of deafblind individuals (Ask Larsen, 2013; Ask Larsen & Dammeyer, 2015).
1.4 The Role of Language Input in Language acquisition
1.4.1 Theoretical Background
In all prevailing theories of language acquisition, the role of language input has been assigned varying importance. Regardless whether one takes the view of Chomsky (1965), who believed that children have innate language learning capacities despite poor input, or Pinker’s view (1994), who believed that language is an instinct, the role of language input has not been neglected. A well-known example of a child who had been denied access to language in her early years is Genie of Curtiss (1977). Genie lived in social isolation and this prevented her the access to language, as well as interacting with anybody else. When Genie was found, she had not acquired language due to her isolation. The story of Genie describes a relative extreme case of linguistic isolation of a child, but throughout the literature more cases of children with restricted input can be found. The language situation of Jim is an example of a child with restricted input (Sachs, Bard, & Johnson, 1981). Jim, a normally hearing child of deaf parents, was neither exposed to spoken language or sign language in the first years of his life. It was reported that the only spoken language input he received was from the television and when he visited the nursery school. The exposure to sign language was also reported as indirect, since exposure to sign language was never directed to the child directly, but could only be observed between adults. After Jim received a linguistic training, in which he was exposed to conventional language, he did not acquire the English structures. The authors therefore concluded that the indirect exposure to spoken and sign language alone, were not sufficient enough for the child to learn the structure of a particular language (Sachs et al., 1981).
The above mentioned cases of Genie and Jim therefore leads to the statement that absence of linguistic input can prevent language to develop, despite the language learning capacities with which we are equipped. Moreover, the documented cases of linguistic isolation and restricted language input suggests that it is the combination of the ability to develop language and exposure to language, which enables language to develop (Sachs et al., 1981; Tomasello, 2001; Tomasello, 2005; Van den Bogaerde, 2000). Not only is linguistic input important for acquiring language, its importance extends to the early stages of child language development. More specifically, linguistic input has repeatedly been identified as a predictive factor of language development. Several studies have shown that the amount (i.e., word tokens) and the diversity of language input (i.e., word types) are related to early child vocabulary growth (Hoff & Naigles, 2002; Hoff, 2006; Huttenlocher, Waterfall, Vasilyeva, Vevea, & Hedges, 2010; Huttenlocher, 1991; Rowe, 2012).
Morgan, 2016; Murphy & Slorach, 1983; Van den Bogaerde, 2000). The unique sociolinguistic environment of these children may have a major impact on their linguistic input and language development. It has frequently been reported that hearing children of deaf parents produce abnormal speech and their syntax has been described as limited (Van den Bogaerde, 2000). This situation may result in a decrease of the quality of linguistic input to which hearing children are exposed. On the other hand, deaf children of hearing parents are at risk of delayed linguistic input, since these parents have to learn sign language after the deaf child is born. As a consequence, these children may be first exposed to a sign language after the first few years (Jamieson, 1995; Lu et al., 2016).
Research has demonstrated that both the quality and the quantity of the linguistic input impacted the language abilities in the atypical language situation of the abovementioned children (Lu et al., 2016; Van den Bogaerde, 2000) Lu et al. (2016) argued that deaf children of deaf parents received more linguistic input compared to hearing children of deaf parents, and the former group appeared to have a more developed vocabulary. It was furthermore reported that the amount of exposure in sign languages was more dependent on language acquisition, as compared to spoken language (Kanto et al., 2013). In addition, Van den Bogaerde (2002) stated that the quality of the linguistic input could be observed in the output of the participating children. All children were offered an increase in mean length of utterance (MLU), and the MLU of the mothers was just ahead of that of the children, whose MLU also increased over time. The quality of the input was furthermore observed on the functional level, demonstrating that as the use of labelling utterances decreased in the input, the decrease was also observed in the output of the children.
1.4.2 The Language Situation of Congenitally Deafblind Children
In the case of deafblindness, not much is known about the quantity and quality of the linguistic input to which these children are exposed. To date, most research has focused on understanding and supporting the early social interactions and development, whereas the focus on symbolic communication has almost entirely been neglected. In a similar way as the group of hearing (and deaf) children of deaf (and hearing) parents, the situation of a deafblind child can also be characterized as an atypical language situation. Like the described children, deafblind children also usually do not share the same language with their parents. Furthermore, these children may also be at risk to limited amount of linguistic input, as well as decreased quality of linguistic input. The thought that lack to linguistic access in the tactile modality as a major factor for the absence of actual language development in the deafblind population has already been suggested (Ask Larsen, 2013; Ask Larsen & Dammeyer, 2015; Ask Larsen, 2016). It is therefore very well possible that the quality and quantity of linguistic input may also affect the language abilities of deafblind children.
and deaf children who do not share the same language as their parents will be discussed. Some of the unique characteristics of this sociolinguistic environment can be extended to the atypical language situation of deafblindness, whereas other characteristics are even more complex in the case of deafblindness. In describing the language input of deaf- and hearing children who do not share the same language as their parents, the importance of the quantity and quality of linguistic input on language development will hopefully be demonstrated. This in turn may contribute to greater insight into the role of input in the complex process of language acquisition in the case of deafblindness. After describing the role of language input in the atypical language situation of deaf- and hearing children who do not share the same language as their parents how this might relate to that of deafblind children, the research questions are formulated in the next section, followed by a description of the design of the study.
The amount of language input
In the literature, not much is reported on the actual amount of language input during the different phrases of language development. In contrast, many studies have focused on the amount of language produced by children. Of the few studies that have examined the language input in the case where either the parent or child was deaf, there appeared to be huge individual differences in the number of utterances to which children were exposed (Kanto et al., 2013; Lu et al., 2016; Van den Bogaerde, 2000). Interestingly, these studies have focused on deaf communities in the Finnish Deaf community (Kanto et al., 2013), the British Deaf community (Lu et al., 2016) and the Dutch Deaf community (Van den Bogaerde, 2000), thereby demonstrating that individual differences in the amount of language input does not appear to be language-specific. Despite the huge individual differences in the number of utterances to which children are exposed at different ages and in different languages, a general trend that has emerged from literature is that the amount of input increases as children grow older (Van den Bogaerde, 2000).
Several studies have also compared the amount of language input in the language situation where both parents and child were deaf (Lu et al., 2016) and hearing children of hearing parents (Van den Bogaerde, 2000) to the situation where either child or parent were deaf. It was reported that deaf parents with deaf children used more signs, compared to hearing parents with deaf children (Lu et al., 2016). Van den Bogaerde (2000) also found that deaf mothers offered less language to their children, compared to hearing mothers to their children. The latter finding was due to the fact that mother seemed to ‘train’ the visual attention of the children, which is a necessary condition before interaction can take place (Kanto et al., 2013; Van den Bogaerde, 2000). In addition, a comparison of sign language and spoken language revealed that signs seem to take longer to produce than words (Bellugi & Fischer, 1972).
their parents. The characteristics and negative consequences of deaf or hearing children and their non-native parents may therefore very well apply to deafblind children. In the deaf language situation, deaf mothers offered less language to their children because they were constantly monitoring and training their children visual attention. In the deafblind language situation, joint attention is achieved tactically and psychical proximity is an additional necessary condition. In addition, it has also been reported that the tactile nature of bodily-tactile perception leads to longer input time (Ask Larsen, 2016).
Language accessibility
In relation to the amount of language input in the language situation of deafness, an important issue is the accessibility of the input (Van den Bogaerde, 2000). In sign language, eye gaze is a necessary condition for communication to take place. If a person is signing, but the child is not looking, no actual language input takes place. Previous research has therefore made a distinction between the amount of input that was being offered to a child and the amount that was accessible to the child. The term ‘uptake’ was first used by Harris (1992), to refer to the amount of input that is accessible to the child. Furthermore, he used the term ‘intake’ to define ‘the features attended to and processed by the child’.
In the case of signing, it was found that on average, 80% of the signing is accessible to the child (Van den Bogaerde, 2000). The relatively high rate was explained by the efforts of the mothers, who ensured accessible input through constantly monitoring visual attention with their children. In contrast, two studies have reported that more than 50% of teacher’s communication was inaccessible to deafblind students (Bruce, 2003; Stillman & Battle, 1987). The authors argued that half of the communication of the teachers’ was characterized as verbal and therefore inaccessible to the deafblind students. Although these results may not be directly comparable, previous research has reported that communication partners tend to use a mix of communication modes, including visual sign language or spoken language, in the interaction with a deafblind child (Dammeyer & Ask Larsen, 2016).
The quality of language input
Previous research has shown that the quality of language input may also vary, and its importance is demonstrated for both the typical language development (Hoff & Naigles, 2002; Hoff, 2006; Huttenlocher et al., 2010; Rowe, 2012), as well as for the atypical language development of children who do not share the same language as their parents (Lu, Jones, & Morgan, 2016; Van den Bogaerde, 2000). The quality of language input includes the structures that are being offered, as well as the vocabulary and the language functions. Several studies have demonstrated that lexical diversity in language input is related to child vocabulary growth (Lu et al., 2016; Rowe, 2012; Van den Bogaerde, 2000). Lexical diversity if often calculated as the number of word types, whereas the quantity of language is often calculated as the number of word tokens. Although there appeared to be considerable variability in the diversity of language input, it was found that hearing parents with deaf children used less sign tokens and types, compared to deaf parents with deaf children (Lu et al., 2016).
Syntactic complexity and structure is often measured by calculating the mean length of utterance (MLU). Although there is not much known about the Mean Length of Utterances (MLU) of the language input during the early period of language development, a general trend is that it appears to slowly increase (Van den Bogaerde, 2000). Previous research has demonstrated that the MLU of the children follow that of their parents, which seems slightly ahead of that from their children (Van den Bogaerde, 2000).
Kyle et al. (1987) found that deaf mothers used fewer questions and more report-type utterances in the communication with their children, compared to hearing mothers. This was explained by the ‘training’ of visual attention of mothers during the early phrases of language development. Van den Bogaerde (2000) found similar proportions of declarative, interrogative, exclamative and imperative functions in the atypical language situation where either the child or mother was deaf, compared to Dutch input in hearing families (Van den Bogaerde, 2000). She furthermore reported that declaratives were dominant in the input, regardless of the language situation, and that questions and imperatives were modestly present. In general, the proportion of imperatives appeared to decrease, whereas only questions seemed to increase over time. The dominance of declaratives in the linguistic input was reflected in the output of the children, which led to the statement, that the amount of labelling of the children was strongly influenced by the interaction and input of their mothers.
Thus, linguistic input may also vary in terms of lexical diversity, structural aspects and functionality. Furthermore, the language that is being offered to deafblind children may also be affected, since. Furthermore, the language that is being offered to deafblind children may not be native-like, because the language the parents use is not their first language. The question that remains unanswered is whether this influences the language acquisition of deafblind children. As there is no clear answer to this question yet, research is needed to describe the input that is being offered to these children. Previous research has suggested that in the atypical language situation where either the parent or child is deaf may decrease the quality and quantity of the language input, and it very well possible that this extends to the language situation of deafblind children.
1.4.3 Conclusion
The role of language input is considered in almost every theory of language acquisition. Although language input has been assigned varying importance, the statement that children need to be at least exposed to a language in order to acquire it, seems beyond dispute (Kanto et al., 2013; Van den Bogaerde, 2000). From the literature, it is clear that both quantity and quality of language input are important related factors for children’s language acquisition. For the atypical language situation where deaf children do not share the same language as their parents, it was found that the amount of language input was more important for sign language acquisition compared to spoken language acquisition (Kanto et al., 2013). Kanto et al. (2013) argued that this was related to the status of sign language as a minority language, which needs more extensive exposure compared to a majority language. Given these findings, it seems especially important to understand the role of language input on language acquisition in the case of deafblindness. The language situation of deafblind children is also characterized by the use of a minority language (i.e., the unusual tactile sign language) and these children also do not share the same language as their parents. As a consequence, their language input may also not be native-like.
2. Research Questions
The sociolinguistic environment of deafblind children in terms of quantity and quality of linguistic input to which they are exposed has yet to be examined, which is the aim of the present explorative paper. In the deafblind language situation, additional issues related to the quantity and the quality of linguistic input are important to consider. This paper examines the situation of one deafblind child, who is called Tom for the purpose of the present study, and the input he receives by either his parents or caregiver. The focus is to describe different qualitative and quantitative aspects of the input and to examine whether these aspects of the input are reflected in the output. The formulated research questions cover the different aspects of the linguistic input (i.e., the communication partners) and output (i.e., Tom).
The first and second research questions are related to the amount of language input. The aim is to explore whether there is a relationship between the input and the output. If language input increases over time, it is assumed that the language output will also increase over time. Research questions three; four and five are related to the quality of the linguistic input. Here, vocabulary, structural and functional aspects of the input are examined, which will then be compared to Toms’ output over time. It is assumed that information about vocabulary, functions and structures offered are important sources of information to determine whether there is a possible relationship between the input that is being offered to Tom and his language development.
RQ 1A: How much language is offered to Tom? RQ 1B: How much language does Tom produce?
It is assumed that the amount of language input is less, compared to the amount deaf and hearing children are exposed to, also since tactile sign language is a minority language. It is furthermore assumed that the amount of language offered will increase over time.
RQ2: How much of the language input can be considered accessible to Tom?
It is assumed that language can be considered accessible only if it is expressed in the tactile sign language and that therefore not all utterances will be accessible to Tom. It is furthermore assumed that a mix of communication modes will be offered to Tom. A second aim is to investigate the way in which communication partners ensure that Tom has access to the linguistic input that is offered to him.
RQ 3A: What kinds of sign types are offered to Tom? RQ3B: What kind of sign types does Tom produce?
RQ 4A: What is the proportion of utterances with a declarative, interrogative and imperative function offered to Tom?
RQ 4B: What is the proportion of utterances with a declarative, interrogative and imperative function produced by Tom?
It is assumed that the functions offered to Tom are similar to that of deaf and hearing mothers offer to their children. It is furthermore assumed that declaratives will form the highest proportion of the input and that this is also reflected in the output.
RQ 5A: What are the structures produced by Tom measured as mean length of utterance (MLU)? RQ 5B: What are the structures offered to Tom measured as mean length of utterance (MLU)?
It is assumed that the MLU offered to Tom will increase over time and that this is just slightly ahead of that of Tom.
3. Method
Participant
Since most deafblind children do not achieve symbolic language, there are only a few cases where the linguistic input as well as the output can be studied. The participating child, who has been given the name Tom for the purpose of the present study, is one of the few deafblind children who had acquired structural properties of a language. In addition, his parents learned tactile sign language soon after Tom’s birth. The situation of Tom therefore provides the rare opportunity to examine both language input as well as the language production of a deafblind child. For this reason, Tom and his parents were selected for the present study. Other considerations to include Tom are related to the relative scarcity of deafblind children whose language development has already been recorded for a period of time. Due to limited time, it was not possible to obtain new longitudinal data for the present paper’s purpose.
Tom is a boy born in Finland who was born both deaf and blind. At the age of eleven months, he received a cochlear implant (CI) on the left side. His vision loss was caused by congenital microphthalmia. Two months after his birth, Tom received a transparent shell prostheses, which offered him some light perception. In addition to his deafblindness, Tom also suffered from choanal atresia and cerebral and cerebellar arachnoid.
both Tom’s parents and his caregiver used spoken language in the communication with him is because the communication consultant of the parents advised this. The communication consultant followed Tom’s communication development at frequent intervals.
Materials
To explore whether the input can be reflected in the output, several video recordings were used to measure the different qualitative and quantitative aspects of the input and output. The use of video-observations and video-analysis is in line with several author, who have argued that this is the best way of studying language and communication in the language situation of deafblindness (Brede & Souriau, 2016; Dammeyer et al., 2015; Janssen et al., 2012; Souriau, 2015).
Tom had been recorded every three months in the first years of his life. The recordings were assessed and used in earlier studies, with the aim of investigating the broad picture of Tom’s language.
Table 1 Overview selected recordings
Recording Age Interaction partner Context Length recording
1 2;0 Mother Giraffe park
2 2;6 Sarah Feeding the horse 2;30
3 3;2 Father Exploring the garden 2;50
4 3;6 Father Father Hammock 1;30
5 4;0 Sarah Talking about a wooden toy 1;35
In total, eleven recordings were available of Tom, of which five were selected for the present study. The video-recordings were made in as real-life settings as possible. Neither the parents nor Sarah were asked to act in a particular way. In contrast, the camera followed what happened during the visit and observed the interaction that took place. Consequently, the context of recordings varies, meaning that in some recordings Tom is playing with a toy, whereas the context of other recordings show an activity with Tom and his communication partners. In addition to the varying context, each recording took place at a different place, with different objects or toys. For the present study, this means that variation in the data may partly be attributed to the use of different settings of spontaneous data.
either his father or Sarah, the caregiver of the day care. Each recording lasted for various minutes. In order to compare different aspects of the language input and output over time, the first minute and a half were selected for analysis to ensure comparability of the videos. A summary of the chosen recordings is given in Table 1.
Given the diverse nature of the recorded videos, the context of each recording is described. The first recorded video depicts a conversation between Tom and his mother about going to the giraffe park together, which is a nearby playground. While sitting on the floor, the conversation is supported by the use of a tactile picture of a giraffe. In the second recording, Tom is communication with Sarah, the caregiver of the day care. Tom is filling a bowl with oat and apples with the help of Sarah. After the bowl is filled, they walk together to the horse. In the third recording, Tom is in the garden with his father, mother and younger brother. In this recording, father and Tom are exploring the box with compost and trees. In the fourth recording, Tom and his father are talking about going to their summer cottage. In the final recording, Tom is playing with a wooden toy. While playing, Tom wonders where the wood came from and who brought it. Here, Tom is communication with Sarah.
Procedure
To analyse the qualitative and quantitative aspects of the linguistic input and output, transcriptions was made of the five video recordings of conversations between Tom and his interaction partners. The video recordings of Tom were already subtitled in English for the purpose of a series of booklets on deafblindness. The original subtitles differentiated between spoken speech, gestures and conventional signs. For the present study, each video recording was analysed on the visual- and tactile signs and spoken speech used by Tom and his interaction partners. Tom sometimes used gestures of which the meaning was not completely understood by his interaction partners. These gestures do not have conventionalized meanings, but were included in the analysis because the meaning could partially be inferred by the context of the conversations. It is possible that these gestures will become signs over time, since previous studies has demonstrated that deafblind children that gestures can lead to meaningful signs, if interaction partners adhere to this properly (Brede & Souriau, 2016). Unintelligible speech also occurred in the video recordings, but was excluded in the present paper because it is not possible to infer meaning to these gestures. Unintelligible speech consisted of signs that were difficult to interpret and were transcribed as /xx/.
also recognizable by pause-length and sometimes speech patterns. In a similar way, the assessment of an utterance unit also considered pauses between various signs to find out what could potentially be considered an utterance. For tactile signed utterances, boundary was further established by noting when hands went to a rest-position (Ask Larsen, 2013; Brede & Souriau, 2016; Dammeyer et al., 2015).
Data analysis
After the transcripts were made, an analysis was done on the quality and quantity of the linguistic input, as well as the linguistic production of Tom per recording. Each aspect of the linguistic input and output is analysed as described below. Analysis was done using descriptive statistics only, since statistical analysis was not possible due to the small sample size.
Quantity of language input and output. For each recording, the total number of spoken words, visual signs and tactile signs the interaction partners produced during the 1;5 minute interaction with Tom was used to measure the input quantity. The total number of spoken words, visual and tactile signs produced by Tom was used to measure the output quantity. Because Tom did not use spoken words, the output quantity only included visual and tactile signs. For analysis, the interaction between Tom and his interaction partner was assessed in the number of words or (tactile) signs of Tom and his interaction partner produced per recording.
Accessibility of language input. To establish how much of the input is accessible to the child, the total number of signs accommodated to the bodily-tactile modality was measured per recording. For each sign, the way in which accessibility of signs was ensured is described.
Variability in vocabulary. The unit of analysis was the total number of signs produced in the bodily-tactile modality by the interaction partners. Lexical diversity was measured by calculating the number of different word categories in the input and output. The following word categories were included: verb; noun; adjective; adverb; preposition; interjection; determiner and question word.
Proportions of declarative, interrogative and imperative functions. Sentence function was measured by coding each utterance of the input and output as declarative, interrogative or imperative. An utterance is here considered a declarative if it includes a statement. Interrogative utterances include those utterances in which a question is being asked. Since it is not entirely clear whether and how questions will be marked in the unusual tactile sign language, each utterance that is considered an interrogative will be discussed in terms of body-tactile modality and the linguistic structure of the utterance. And finally, an utterance is here considered an imperative if the function of the utterance is to request an object or action.
utterance for both the input and output per recording. To calculate the MLU of the input, only tactile signs were included, whereas visual signs were also included to calculate the MLU of the output.
Reliability for transcription and segmentation
4. Results
In this section, the results of the research questions are presented. Analysis of the research questions was done using descriptive statistics only, because statistical analysis was not possible due to the small number of participants and number of observations
In general, the results are presented per research question. Thus, all five recordings are presented per research question to describe the qualitative and quantitative aspects of the linguistic input produced by the interaction partners of Tom. In order to examine whether the input might be reflected in the output, the qualitative and quantitative aspects of Toms’ will also be described over time.
RQ 1: How much language is offered to Tom and how much language does Tom produce? Table 2 displays the total number of words and signs produced in the input and output in 1;5 minutes of interaction per video recording. All words and signs were included in the present analysis and it appears that the amount of words/ signs does not increase over time. The amount of input appears to be higher in the first three video recordings and lower in the latter two. However, a different trend emerges when looking at the amount of output over time. It appears that, overall, the amount of signs in the output increases over time, with the most signs produced at 4;0 years.
The amount of language input in the case of deafblindness at different phrases of language development is compared to three other language situations, namely the amount of input deaf and hearing children of deaf parents are offered and the amount of input hearing children of hearing children are offered. Table 4 presents an overview of the number of utterances for 10 minutes of interaction for the deaf and spoken language situation. To determine whether the amount of language input is comparable to the input of other language situations, the data is corrected for 10 minutes (see Table 3).
The first thing to notice is that Tom is offered more input at the age of 2;0 compared to the amount deaf and hearing children receive from their deaf parents. At the other moments, the amount of input falls between the amounts of input deaf mothers offer to their deaf or hearing children. Thus, no great differences in the number of utterances produced in the input appear when comparing the amount of input to the deaf language situation. Since no data was available of the spoken language situation, comparison was not possible.
Table 2 Total number of words/ signs produced by interaction partner and Tom in 1;5 minutes of interaction T1 (2;0)
Giraffe park
T2 (2;6) Feeding the horse
T3 (3;2) Exploring the garden
Table 3 Total number of utterances produced by interaction partner and Tom in 1;5 minutes of interaction T1 (2;0)
Giraffe park
T2 (2;6) Feeding the horse
T3 (3;2) Exploring the garden
T4 (3;6) Father Hammock T5 (4;0) Wooden toy Input 30 (198)* 22 (145)* 21 (138)* 15 11 Output 8 9 5 13 9
* session corrected for 10 minutes
Table 4 Total number of utterances produced by deaf and hearing mothers in 10 minutes
Source 2;0 2;6 3;0
Van den Bogaerde (2000) Deaf mothers to deaf children* Deaf mothers to hearing children*
133 150 123 172 161 137 Van der Stelt (1993)
Hearing mothers to hearing children 170 – 200
* these sessions were corrected for 10 minutes and indicate the average score of three mothers
RQ 2: How much of the language input can be considered accessible to Tom?
The second research question is related to the amount of linguistic input that can be considered accessible to Tom. In the previous paragraph, it was suggested that accessibility of language input is especially important to consider in the deafblind situation. This is explained by the combined hearing and vision loss of deafblind children, which means that that spoken words and visual signing may not be perceived and processed. Consequently, accommodating signs to the bodily-tactile modality is a necessary condition to ensure accessibility of the linguistic input.
Accessibility of the input was assessed in terms of language modality used. In total, three different modalities occurred in the data as a whole; spoken words, visual signs and bodily-tactile signs. The total number of tokens produced by interaction partner per language modality is presented in Table 5. After analysis, it appeared that spoken words and tactile signs were evident in the language input, whereas visual signing was only evident in language output.
Table 5 Total number of words categorized by language modalities produced by interaction partner of Tom in 1;5 minutes of interaction Language modality T1 (2;0) Giraffe park T2 (2;6) Feeding the horse
T3 (3;2) Exploring the garden
T4 (3;6) Father Hammock T5 (4;0) Wooden toy Spoken words 46 (72%) 30 (48%) 43 (61%) 6 (15%) 9 (25%) Tactile signs 18 (28%) 33 (52%) 28 (39%) 34 (85%) 28 (75%) Total words 64 63 71 40 37
As demonstrated in Table 5, most spoken words (calculated as the percentage of the total number of words produced) are found at T1; T2 and T3 and the amount of spoken words decreases over time. In contrast, the amount of bodily-tactile signs (calculated as the percentage of the total number of words produced) is relatively low at T1, accounting for roughly 25% of the language input. However, only six months later, the use of bodily-tactile signs already accounts for roughly 50% of the input.
On average, it appears that 48% of the language input is spoken words, which may not be perceived or processed by Tom and is therefore considered inaccessible. Despite the relatively low rate of ‘uptake’ (i.e., the amount input that can be considered accessible), it appears that, overall, the amount of spoken words in the input decreases over time, whereas the amount of bodily-tactile signs in the input tends to increase over time.
The second aim was to examine the way in which accessibility of the input was ensured. In the interaction with Tom, all signs of the input were accommodated in the bodily-tactile modality. The communication partners of Tom ensured accessibility of the input by grabbing Tom’s hands before they started to sign, therefore making sure that Tom had physical access to the linguistic input. The space for expressing tactile signs of the interaction partner is not consistent, in that sometimes the tactile signs were placed on Tom or on the body of the interaction person self. The signs of Tom were all produced visually, either in space or on his own body, which is in accordance with the sign system of his country. After he signed visually, it was evident that he grabbed the hands of his communication partner.
Research Question 3: What kind of signs is produced in the input and output?
Table 6 Total number of tokens categorized per word class produced by interaction partner in 1;5 minutes of interaction
Categories T1 (2;0) Giraffe park
T2 (2;6) Feeding the horse
T3 (3;2) Exploring the garden
T4 (3;6) Father hammock T5 (4;0) Wooden toy Verb 4 12 2 6 5 Noun 11 18 13 12 10 Pronoun 2 3 2 Adjective 2 1 2 1 4 Adverb Preposition 1 8 5 Interjection 2 1 4 Determiner 1 2 Question Word 6 1
It appears that the vocabulary of the input at T1 consists of verbs, nouns, adjectives and prepositions and that these word categories are therefore offered first to Tom. Over time, the variability vocabulary of the input increases in that interjections and determiners appear in the input at the age of 3;2. Four months later, question words also appear in the input. Thus, it appears that variability of vocabulary offered increases over time in terms of word categories offered. The use of more word categories in the input is not only evident over time, but also within interactions. At T1, four different word categories are offered to Tom in 1;5 minutes of interaction, whereas at T5, seven different word categories are used in 1;5 minutes of interaction.
At all five moments, nouns were most used by the communication partners, followed by verbs. Furthermore, verbs and adjectives were also used at all five moments. Of all word categories, only adverbs seem to be absent in the input.
Table 7 Total number of tokens categorized per word class produced by Tom in 1;5 minutes of interaction Categories T1 (2;0)
Giraffe park
T2 (2;6) Feeding horse
T3 (3;2) Exploring the garden
Variability of the vocabulary of the output is presented in Table 7. The use of verbs and adjectives appears first in the vocabulary of Tom, followed by nouns. Form the age of 3;2, prepositions appear in Tom’s vocabulary and pronouns from the age of 3;6. Furthermore, the high amount of nouns at all ages is most striking. Similar to the language input, it appears that variability of the vocabulary of the output increases over time in terms of word categories offered. Again, the growth of vocabulary is not only evident over time, but also within conversations. At the age of 2;0, Tom uses two different word categories in 1;5 minutes of interaction, whereas he uses six different word categories at the age of 4;0. With every new word category Tom uses, as he grows older, its use is already evident in the input prior to its use in the output.
As can be seen in Table 7, the highest amount of verbs can be found at age 2;0. At first, this might seem surprisingly, given that previous research has repeatedly demonstrated that early language acquisition might be characterized by a noun bias. Therefore, an analysis of the lexical richness was done for verbs and nouns by analysing the number of repeated verbs and nouns for the output. Table 8 presents the total number of verbs and nouns in the output and the number of repeated verbs and nouns.
At the age of 2;0, Tom uses two different verbs, namely slide and swing. Overall, the number of repeated verbs decreases and the number of verb types is higher over time. The complexity of verbs also growths, as transitive verbs appear from the age of 2;6. At this age, Tom uses ‘give’ as an intransitive verb. At the age of 3;0, ‘give’ was used to indicate ‘give to me’. At the age of 3;6, another transitive verb appears in his signing, which can be seen in (4) in the following example:
(1) Father How (shall we go) (2) Father (By) boat
(3) Father Tom engine put-on himself (4) Tom Push father myself (5) Father Tom yourself push
* the words between brackets presents spoken words
In contrast, the number of noun types does not increases over time. The highest amount of noun types is found at the age of 3;6, where Tom uses eight different nouns.
Table 8 Variability in verbs and nouns in the output
Age Repeated Number of noun types Repeated Number of verb types
2;0 5 2
2;6 3 4 1 5
3;2 0 3
3;6 4 8 0 3
Research Question 4: proportions of utterances with a declarative, interrogative and imperative function
The fourth research question is interested in the proportions of utterances with a declarative, interrogative and imperative function in the language input and output. All linguistic utterances accommodated in the tactile modality were included in the present analysis. The unit of analysis was the linguistic utterance, and single-sign utterances were also included. For analysis, each utterance was first labelled as a declarative, interrogative or an imperative function. The function of the single-sign utterances was also determined on the basis of context and conversation. Consider the following example from the context Father Hammock:
(1) Father What with (us) in bag (2) Father What (food)
(3) Tom Food (4) Tom Baked roll
* the words between brackets presents spoken words
Although spoken words were excluded in the analysis, for the purpose of the present example they are presented between brackets. The single-sign utterances (3) and (4) of Tom were coded as declaratives, since it is clear from the context that these utterances are answers of the questions (1) and (2). Furthermore, (1) and (2) were coded as an utterance with an interrogative function.
The functions of utterances of the language input are presented in Table 9. At all five moments, the majority of utterances in the input were labelled as declaratives. At the age of 2;6, interrogatives and imperatives are also used, which are furthermore modestly present in the input. The dominance of declaratives in the input is also reflected in the output over time (see Table 10). Tom starts to use the imperative function from the age of 3;6, after it has already been used in the input. At all periods of time, interrogatives are absent in the output.
Table 9 Proportions of utterances with a declarative, interrogative and imperative function produced by interaction partner in 1;5 minutes of interaction
Utterance function
T1 (2;0) Giraffe park
T2 (2;6) Feeding the horse
T3 (3;2) Exploring the garden
Table 10 Proportions of utterances with a declarative, interrogative and imperative function produced by Tom in 1;5 minutes of interaction Utterance function T1 (2;0) Giraffe park T2 (2;6) Feeding horse T3 (3;2) Exploring garden T4 (3;6) Father Hammock T5 (4;0) Wooden toy Declarative 8 9 5 12 7 Interrogative Imperative 1 2 Total utterances 8 9 5 13 9
Research Question 5: what are the structures produced by either Tom or his communication partner measures as mean length of utterance (MLU)?
The quality of the linguistic input was also measured in terms of structures offered. The Mean length of Utterances (MLU) was used to measure structures and also evaluates the syntactic complexity of the structures for both the language input and output. To calculate the MLU of the language input at various moments of time, only tactile signs were included. Thus, if an utterance in the language input included both spoken words and tactile signs, only the number of tactile signs in the utterance as used to measure the MLU. MLU in the output was assessed in a similar way, with the only exception that the number of visual signs in one utterance was used to measure the MLU of the output.
Table 11 presents the mean value of the MLU. At the age of 2;0, the lowest MLU of the input can be found. At this age, most utterances offered to Tom are single-sign utterances. One 3-sign utterance was offered to Tom at age 2;0. At the age of 2;6, the number of single-sign utterances decreases and more 2-and-3-sign utterances are offered to Tom. Again, 2-and-3-sign-utterances are the longest utterance produced in the input. In general, the MLU increases over time. Single-sign utterances decline as Tom gets older. At the age of 3;6, 5-sign-utterances are used in the input. Overall, the input shows an increase in length with time.
In a similar way as the input, the MLU of Tom shows a clear development over time. When Tom is 2-years-old, he only produces single-sign utterances. At age 2;6, many single-sign utterances can still be found, but 2-and-3-single-sign utterances also appear. As Tom grows older the number of single-sign declines and the number of multi-sign utterances increases, in particular the 2- and 3-single-sign utterances. Although a similar development of the input is evident in the output over time, it always stays behind of the input. In other words, it is only after (for example) 3-sign-utterances are offered in the input, they can later be found in the output.
Table 11 Mean values of MLU produced by interaction partner in 1;5 minutes of interaction Mean value MLU T1 (2;0) Giraffe park T1 (2;6) Feeding horse T2 (3;2) Exploring garden T3 (3;6) Father Hammock T4 (4;0) Wooden toy Input 1,4 1,7 2,5 2,4 2,8 Output 1 1,3 1,2 1,3 2
5. Discussion
In the present explorative paper, the role of language input is examined in the atypical language situation of one deafblind boy in the interaction with his parents and caregiver. To date, little is known about the sociolinguistic environment of deafblind children, including the input they receive. Consequently, the question whether these children receive adequate input for them to acquire language has yet to be answered. Given that previous research has repeatedly demonstrated that the majority of these children do not make the transition to symbolic language development, it is very well possible that this may point to the importance of language input as an important aspect of the sociolinguistic environment, in which language acquisition takes place. Numerous studies have already demonstrated the importance of language input for language acquisition in the typical and atypical language situation of children and the current explorative paper adds to this line of research, since it is the first paper to describe and consider language input as an important part of the sociolinguistic environment in the case of deafblindness.
Since it was not possible to use statistical analysis, the goal was not to establish a causal relationship between language input on the one hand, and language acquisition on the other hand. Instead, the aim was to explore whether language input as an important part of the sociolinguistic environment, was reflected in the output. Moreover, the goal was to describe the qualitative and quantitative aspects of language input, as an important aspect of the sociolinguistic environment of Tom.
The amount of language input
