Theories of language acquisition: learning, nativist and interactionist

Learning theory (Skinner, 1957)

Language is learned like any other behaviour through operant conditioning:

• Babbling sounds that resemble words are reinforced by parents' attention and praise (shaping), so they become more frequent and more word-like.
• Children imitate speech they hear (social learning), and correct speech gets what they want (a 'mand': 'milk' gets milk).

Evaluation: explains accents and vocabulary, which clearly come from the environment. But parents rarely correct grammar and often reinforce untrue but well-formed sentences; children produce sentences they have never heard and overgeneralise ('gived'), which imitation cannot explain.

Nativist theory (Chomsky)

• Children have an innate language acquisition device (LAD), later described as universal grammar: built-in knowledge of how grammar works, tuned by the language heard.
• Poverty of the stimulus: the speech children hear is incomplete and full of errors, yet they work out complex grammar quickly, so some knowledge must be innate.
• The same stages appear across cultures, and overgeneralisations show rule-finding.

Evaluation: explains speed and universality. But the LAD cannot be directly observed (hard to test, less falsifiable), and it underplays the role of social interaction and the different speeds at which children learn depending on the speech they hear.

Interactionist theory (Vygotsky)

Language develops through social interaction with more knowledgeable others. Speech starts as social speech (communicating with others), becomes private speech (talking aloud to guide oneself, around ages 3 to 7) and then inner speech (silent thought). Language is a cultural tool that shapes thinking, so language drives cognitive development, the reverse of Piaget.

Adults scaffold language: they adapt their speech to the child, expand the child's utterances and take turns in conversation.

Evaluation: fits evidence that interaction matters and combines nature (a capacity to learn) with nurture (social input). But it says less about how grammar itself is acquired.

Comparing the theories

Worked example

A 3-year-old says 'I goed to the park'. Which theory does this support, and which does it challenge?

1. Adults do not say 'goed', so the child did not imitate it, which challenges learning theory.
2. The child has applied the past-tense rule '-ed' to an irregular verb: rule finding, which supports Chomsky's nativist idea of innate grammar.

Answer: Supports nativist theory; challenges learning theory.

Check yourself

1. The language acquisition device is
   • a reinforcement schedule proposed by Skinner
   • a stage of babbling
   • an innate mental mechanism for acquiring grammar proposed by Chomsky
   • a type of scaffolding
   Show answer

   an innate mental mechanism for acquiring grammar proposed by Chomsky. Chomsky's nativist idea.

2. The 'poverty of the stimulus' argument says
   • children acquire complex grammar from incomplete, imperfect input, so some knowledge must be innate
   • poor children learn language more slowly
   • children learn language only when reinforced
   • language needs a rich vocabulary to develop
   Show answer

   children acquire complex grammar from incomplete, imperfect input, so some knowledge must be innate. The input is not enough to explain the output.

3. Parents smiling when a baby's babbling sounds like 'mama' is an example of
   • the language acquisition device
   • private speech
   • reinforcement in learning theory
   • overgeneralisation
   Show answer

   reinforcement in learning theory. Reinforcement makes the sound more likely.

4. In Vygotsky's account, a child talking aloud to guide herself through a puzzle is using
   • inner speech
   • private speech
   • telegraphic speech
   • a holophrase
   Show answer

   private speech. Self-directed speech aloud, later internalised.

5. Which theory places most emphasis on nurture?
   • Nativist theory
   • Piaget's theory
   • Universal grammar
   • Learning theory
   Show answer

   Learning theory. Skinner: language is learned from the environment.

6. Which observation is most difficult for learning theory to explain?
   • Children have local accents
   • Children produce sentences they have never heard
   • Children learn words for things in their home
   • Children use words that get them what they want
   Show answer

   Children produce sentences they have never heard. Novel sentences cannot be imitations.

7. Explain one strength of Chomsky's nativist theory of language acquisition.
   Show answer

   It explains why children everywhere pass through the same stages and learn complex grammar so quickly, even from imperfect input, which supports an innate language acquisition device.. Evidence and link to innateness.

Practise with instant feedback Print this lesson

Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 6 (November 2024, first assessment January 2026)
• Psychology of Language (open textbook): Language development
• OpenStax Lifespan Development: 1.3 Major theories and theorists (including Vygotsky)
• Pearson WPS03/01 examiners' report, January 2025

Last updated 8 November 2026. Spotted a mistake? Tell us.