Course taster

Theoretical explanations of language development

In this part of the unit, we will examine key theoretical explanations of how children learn language, focusing specifically on the behaviourist, nativist and social interactionist theories of language development. The following sections will examine different theoretical explanations and the key thinkers behind them.


BF Skinner circa 1950

B F Skinner circa 1950
Image source: Wikimedia Commons (Accessed on 06.02.2023)

Behaviourism is one of the earliest scientific explanations of language acquisition and was introduced by Skinner (1957) in his book titled Verbal Behaviour. According to Skinner, language is learned through a child's environment with caregivers, such as parents, and other adults acting as models of language. In short, children observe the language that is spoken around them by adult models and imitate the words that they hear. A key aspect of the behaviourist theory is the notion that children learn language through positive and negative reinforcement principles in which words are associated with meanings. To illustrate, a child who is praised by their mother for uttering a word or sentence correctly will find this outcome rewarding which, in turn, enhances their language development.

Nativist theory

Noam Chomsky 1977

Noam Chomsky 1977
Image source: Wikimedia Commons (Accessed on 06.02.2023)

Noam Chomsky and other nativist theorists have criticised behaviourism for being too simplistic; instead arguing that humans acquire language too quickly for it to be learned solely through observation and imitation. Rather, nativist theory proposes that children are biologically programmed to learn language from birth and possess innate learning mechanisms. Chomsky (1957) introduced the concept of a Language Acquisition Device (LAD); a mental organ like a heart or liver that exists inside our brain and helps us to learn language. In addition to the LAD, Chomsky proposed that humans are born with inbuilt knowledge of the structure or syntax of language. This is known as a theory of Universal Grammar, which consists of the basic grammatical rules that characterise all languages. The idea of Universal Grammar is that we have biological grammatical categories inside our heads, such as a noun category and a verb category that facilitates language development in children (Bjorklund, 2005). Universal Grammar, therefore, enables us to instinctively combine these categories such as nouns (e.g., a boy) and verbs (e.g., eats) into meaningful phrases (e.g., a boy eats). Due to having an innate knowledge of grammatical rules and sentence structure, a child's task is simply to learn the words of their language as Universal Grammar will automatically help to assemble these words into coherent sentences. As such, nativist theory postulates that language is produced by a child's biology, and that we are specially prepared to learn language from birth.

Stop and think

Did you learn another language (e.g., French, Spanish, Italian or German) when you were at secondary school or college? How easy or difficult was it for you to learn another language? It may be that you found it difficult to learn a different language, which can be explained by the critical period hypothesis, which we will now examine.

Critical period hypothesis

To fully develop competencies in their language abilities, Lenneberg (1967) stated that children must be exposed to language early in life during a critical or sensitive period of brain development that lasts from birth until puberty. This critical period reflects the underlying idea that our nervous system becomes less flexible as we get older causing language learning to become more difficult. In support of the critical period hypothesis, Locke (1993) highlighted cases of feral children and people who had been socially deprived or isolated during their early childhood who consequently demonstrated very limited mastery of language.

Please now watch the following seven-minute video, which presents an overview of the famous case of Genie Wiley, a 13-year-old girl who had been kept in solitary confinement during her childhood. This is evidence of how a failure to develop language during the critical period has been shown in a real-life case study.

Genie Wiley: America's Feral Child

View Genie Wiley: America's Feral Child video transcript

Further reading

You are encouraged to read the following article about Genie published in The Guardian newspaper. It includes further discussion of language and the importance of the critical period.

If interested, you may also wish to access the following book about Genie written by Susan Curtiss, an American linguist who studied the case in depth. The book is comprehensive, but it is recommended that you read pages 207–211 as this part focuses specifically on the critical period hypothesis. The book is available online through the online reading list (The link to the online reading list is not available in this course taster).

Curtiss, S. (1977). Genie: A psycholinguistic study of a modern-day "wild child". Academic Press.

Social interactionist theory

Jerome Bruner 1936

Jerome Bruner 1936
Image source: Wikimedia Commons (Accessed on 06.02.2023)

Most researchers who support the social interactionist theory of language development tend to largely agree with nativist ideas (i.e., that humans are biologically predisposed to learn language from birth). In contrast to nativist theory, however, the social interactionist perspective attaches much greater importance to the social environment in helping a child to learn language (Bjorklund, 2005). Scholars such as Jerome Bruner, for example, have emphasised the essential role of parents and other adults in supporting children's language development. Bruner (1983) argued that language is carefully presented to children by the people around them to match the child's current abilities. In other words, children learn language predominantly through social experience and interaction with adults. Moreover, language development is facilitated through child-directed speech; a special type of "baby talk" used with very young infants that is characterised by high pitched exaggerated tones, simplified forms of adult words, many questions and repetitions. This simpler form of speech was originally known as motherese (Snow, 1972), but the term was later replaced with child-directed speech (also known as infant-directed speech) as its use has also been found among fathers and four-year-old children.

Please now watch the following one-minute video which demonstrates child-directed speech in action.

Better Brains for Babies - Infant-Directed Speech

View Better Brains for Babies - Infant-Directed Speech video transcript

Stop and think

Pause for a moment to reflect on the video. Have you ever used child-directed speech yourself when talking to a very young infant? Or have you ever seen another person use child-directed speech? Try to think of an example from your own life.