Another communicative tool available to infants is the use of vocalisations such as babbling, it has been proposed that from as early as one month infants begin to recognise phonemes such as the consonant sounds d and s and soon after distinguish the vowels a and i (Hoff-Ginsberg, 1997). From this rudimentary process infants commence the process of language acquisition by using cues during naturally occurring speech of those around them, for instance, the rhythm, pauses, pitch and the emphasis placed on different phonemes that facilitates the identification of the boundaries between words (Keenan, 2002).
The influence of this progressive process can be seen around the age of six months when cries that were originally utilised to signal distress are adapted to serve communicative functions (Berk, 2000). The discovery of this phenomenon came in a study conducted by Bell and Ainsworth (1972), it was found that mothers with a short response latency led to infants’ use of distressful crying less which in turn led to infants developing clearer and more specific communicative signals toward the end of the first year (Bell, Ainsworth, 1972). Herein is a small number of the phenomena involved in the acquisition of language, the next step is to ascertain how these processes are to be interpreted.
Different theorists would apply the above processes in different ways according to their own point of view. Learning Theory (Skinner, 1957) focuses on operant conditioning processes, with the development of language occurring through parental selective reinforcement of ‘appropriate’ linguistic behaviours. In the subsequent twenty years Bandura (1977) went on to highlight that observational learning is the main process involved in language acquisition, the imitation of others results in the learning of complex and lengthy phrases. The reinforcement of such imitation and its generalisation allows the application of newly learnt language to new situations, and feedback helps children understand the appropriateness of such (Bandura, 1977).
Some have criticised the Learning Theory approach by stating that the rapid nature of language acquisition and the long periods of time over which principles of operant conditioning and observational learning influence behaviours, because of this discrepancy it appears unlikely that the latter can be applied to the former (Keenan, 2002). Moreover, the language children are exposed to rarely include instances of complex structures, and this stimulus poverty means that it would be difficult for children to adequately learn how to apply such complex rules in their own language use (Chomsky, 1968).
An extension of Skinner (1957) and Bandura’s (1977) learning theories is Vygotsky’s Social Development Theory (Vygotsky, 1978). Vygotsky (1978) speculates that social interaction plays a fundamental role in the development of cognition. According to Vygotsky (1978) every function in the child’s cultural development appears twice, firstly, on the social level, and later, on the individual level. The first major component of language development occurs between the infant and the primary care-giver, interpsychologically, and secondly inside the child, intrapsychologically. This applies equally to voluntary attention, to logical memory, and to the formation of concepts.
All the higher functions originate as actual relationships between individuals (Vygotsky, 1978). A second aspect of Vygotsky’s theory is the idea that the potential for cognitive development depends upon the “zone of proximal development” (ZPD). A level of development attained when children engage in social behaviour. Full development of the ZPD depends upon full social interaction. The range of skill that can be developed with adult guidance or peer collaboration exceeds what can be attained alone. Vygotsky’s (1978) theory was an attempt to explain consciousness as the end product of socialisation. For example, in the learning of language, our first utterances with peers or adults are for the purpose of communication, but once mastered they become internalised and allow “inner speech” (Vygotsky, 1978).
Nativist Theory (Chomsky, 1957) posits that there are shared assumptions in language acquisition, in other words, certain grammatical concepts that are common to all languages and are thus innate. Chomsky (1957) contends that children have a biological disposition to language acquisition and it is children’s innate hypotheses regarding language allow extraction of the principles which govern this process (Chomsky, 1957). Chomsky (1968) states that the innate mental structure that is responsible for language is the language acquisition device (LAD). The LAD contains the common grammatical concepts, or universal grammar, which allows its use with any language. Once the principles of the specific language are extracted by the LAD, these principles are built into the LAD in order to allow interpretation of further speech (Chomsky, 1968).
Critics of nativist theory ask; what kind of universal language is universal to all languages? (Keenan, 2002) Another difficulty for nativist theory is that the lengthy time period over which understanding of grammatical rules emerges suggests that if this knowledge is innate, it must be more limited than that proposed by nativist theorists (Keenan, 2002). Furthermore, there is little neurological evidence for a biological predisposition to language learning, such as the LAD (Keenan, 2002).
A third approach to the development of language in human infants is the interactionist theory (Bruner, 1983). According to Bruner (1983) the social support and social context of language acquisition is as important as biological factors. Scaffolding, ‘motherese’ and expansion all facilitate the effective operation of the strong biological predisposition towards language acquisition. This collection of strategies has been termed the language acquisition support system (LASS) (Bruner, 1983). Opponents of Interactionist theory cite that direct feedback on the appropriateness of language is rare and cannot be regarded as an essential element of any LASS (Keenan, 2002).
The processes and phenomena described herein have real ecological implications for the diagnosis and treatment of hearing and visually impaired infants, and a key role in the diagnosis and treatment of infants with autism (Yingling-Wert, Neisworth, 2003, Dautenhahn, 2002, Baron-Cohen, 1995). A unified theory of language acquisition during infancy would be a step forward in the understanding of how theses conditions develop and how ‘normal’ development occurs.
References
Acredolo, L.P. Goodwyn, S.W. (1990) Sign Language in Babies: The Significance of Symbolic Gesturing for Understanding Language Development. In R. Vasta (Ed.) Annals of Child Development. Vol. 7 pp. 1-42, Greenwich, CT; JAI Press.
Bandura, A. (1977) Social Learning Theory. Englewood Cliffs, NJ; Prentice-Hall.
Baron-Cohen, S. (1995) Mindblindness: An Essay on Autism and Theory of Mind. Cambridge MA; MIT Press.
Bates, E. (1976) Language and Context: The Acquisition of Pragmatics. New York: Academic Press.