Key Theories of Language Acquisition

Why This Matters

Language acquisition sits at the heart of cognitive psychology—it's where nature vs. nurture, biological constraints, social learning, and information processing all collide. When you're tested on this material, you're not just being asked to match theorists to their ideas. You're being assessed on whether you understand the fundamental debate: Is language learned, innate, or something in between? These theories represent different answers to that question, and each one emphasizes different cognitive mechanisms.

The AP exam loves to test your ability to compare perspectives and apply them to scenarios. A free-response question might describe a child's language development and ask you to explain it through multiple theoretical lenses. Don't just memorize names and dates—know what cognitive process each theory prioritizes and how they contradict or complement each other. That's where the points are.

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Nature-First Approaches: The Biological Foundation

These theories argue that language is fundamentally hardwired into the human brain—we're born ready to acquire it, and experience simply activates what's already there.

Nativist Theory (Noam Chomsky)

• Universal grammar—Chomsky proposed that all humans are born with an innate mental framework containing the grammatical rules common to all languages
• Language Acquisition Device (LAD) is the hypothetical brain mechanism that enables children to rapidly acquire complex grammar despite limited input
• Poverty of the stimulus argument suggests children learn grammatical rules they've never been explicitly taught, proving language can't be purely learned

Critical Period Hypothesis (Eric Lenneberg)

• Biological window—Lenneberg proposed that optimal language acquisition occurs between birth and puberty, after which the brain loses plasticity for language learning
• Genie case study provides tragic evidence: a girl isolated until age 13 never fully acquired grammar, supporting the hypothesis
• Second language acquisition research shows adults can learn vocabulary but struggle with native-like pronunciation and grammar, consistent with critical period effects

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Nurture-First Approaches: Learning from the Environment

These theories emphasize that language is acquired through experience—whether through reinforcement, social interaction, or statistical patterns in input.

Behaviorist Theory (B.F. Skinner)

• Operant conditioning—Skinner argued children learn language through reinforcement; correct utterances are rewarded, incorrect ones are ignored or corrected
• Imitation and shaping explain how children gradually approximate adult speech through successive reinforcement of closer approximations
• Verbal Behavior (1959) was Skinner's book applying behaviorist principles to language, famously criticized by Chomsky for ignoring creativity in language use

Social Interactionist Theory (Lev Vygotsky)

• Zone of Proximal Development (ZPD)—language skills develop through scaffolded interactions with more capable speakers who provide support just beyond the child's current ability
• Language as a cultural tool means children don't just learn words; they learn how their community uses language to think, categorize, and solve problems
• Private speech (talking to oneself) demonstrates language's role in cognitive development—children internalize social speech to guide their own thinking

Usage-Based Theory (Michael Tomasello)

• Intention-reading—Tomasello emphasizes that children learn language by understanding what speakers mean, not just what they say
• Pattern extraction from high-frequency constructions allows children to generalize grammatical rules from specific examples they've heard repeatedly
• Joint attention is critical: children learn words when adults and children focus on the same object together, linking social cognition to vocabulary acquisition

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Cognitive-Developmental Approaches: Language Follows Thought

These theories position language acquisition as dependent on broader cognitive development—children can only express what they can first understand.

Cognitive Theory (Jean Piaget)

• Cognition precedes language—Piaget argued children must first develop mental concepts before they can learn words for them (e.g., object permanence before "gone")
• Stages of development constrain language: a preoperational child uses egocentric speech because they can't yet take others' perspectives
• Constructivism means children actively build linguistic knowledge through exploration, not passive absorption—language reflects their current cognitive stage

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Computational Approaches: Language as Information Processing

These theories model language acquisition as pattern recognition and neural network learning—the brain extracts statistical regularities from linguistic input.

Connectionist Theory (Jeffrey Elman)

• Neural network models—Elman demonstrated that artificial networks can learn grammatical patterns without built-in rules, challenging Chomsky's nativist claims
• Statistical learning means the brain tracks probabilities: which sounds follow which, which words co-occur, which sentence structures are common
• Gradual weight adjustment in networks mirrors how children slowly refine their language through exposure, making errors that reflect incomplete pattern learning

Parallel Distributed Processing Model (McClelland & Rumelhart)

• Simultaneous activation—PDP models propose that reading a word activates spelling, sound, and meaning representations at the same time, not in sequence
• Distributed representations mean concepts aren't stored in single locations but across networks of connections, explaining why brain damage causes partial rather than total language loss
• U-shaped learning curves are explained: children say "went," then overgeneralize to "goed," then return to "went" as the network adjusts

Dual-Route Model (Coltheart)

• Lexical route—familiar words are recognized as whole units through direct visual-to-meaning mapping, explaining fast reading of common words
• Phonological route—unfamiliar words are decoded through grapheme-to-phoneme conversion rules, explaining how we can read nonsense words like "blint"
• Dyslexia subtypes are explained by selective damage to one route: surface dyslexia (impaired lexical route) vs. phonological dyslexia (impaired phonological route)

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Integrative Approaches: Beyond the Nature-Nurture Divide

These theories attempt to synthesize multiple factors, arguing that language emerges from the interaction of biology, cognition, and environment.

Emergentist Theory (Elizabeth Bates)

• No dedicated language module—Bates rejected Chomsky's LAD, arguing language emerges from general cognitive abilities like memory, attention, and pattern recognition
• Dynamic systems perspective means language development is nonlinear and context-dependent, with small changes in input potentially causing large developmental shifts
• Competition model proposes that learners weigh multiple cues (word order, morphology, animacy) differently depending on their language, explaining cross-linguistic variation

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Quick Reference Table

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Self-Check Questions

1. Compare and contrast: How would Skinner and Chomsky each explain a child who says "I goed to the store"? What does this error reveal about the limits of behaviorist theory?

2. Which two theorists would most strongly disagree about whether language requires a specialized brain module? Explain the core of their disagreement.

3. A researcher finds that children in highly interactive households develop vocabulary faster than children who watch educational videos alone. Which two theories best explain this finding, and why?

4. FRQ-style: Describe how the Critical Period Hypothesis and Social Interactionist Theory could both be used to explain difficulties in second language acquisition for adult immigrants. Where do they agree and disagree?

5. If a patient has damage that impairs reading of familiar words but preserves the ability to sound out nonsense words, which model best explains this pattern? What route is damaged?