Factors Affecting Second Language Acquisition

Why This Matters

Second language acquisition (SLA) sits at the intersection of cognitive psychology, developmental psychology, and social psychology—three areas the AP exam loves to test together. You're being tested on your ability to explain why some learners achieve fluency while others plateau, and how factors like critical periods, motivation types, and cognitive processes interact to shape language learning outcomes. These concepts connect directly to broader themes you'll see throughout the course: nature vs. nurture, individual differences, and the role of environment in shaping behavior.

Don't just memorize a list of factors—know what psychological principle each one demonstrates. When an FRQ asks about language development, you need to identify whether the question targets biological constraints (like the critical period), cognitive mechanisms (like working memory), or social-environmental influences (like immersion). Understanding the category of each factor will help you construct stronger, more conceptually organized responses.

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Biological and Developmental Factors

These factors reflect the brain's built-in timeline for language learning. Neuroplasticity decreases with age, making certain aspects of language acquisition—especially pronunciation—harder to master after childhood.

Age of Acquisition

• Critical period hypothesis—proposes an optimal window for language learning, typically before puberty, when the brain is most receptive to phonological input
• Younger learners achieve more native-like pronunciation and intuitive grammar use due to greater neural plasticity
• Older learners compensate with stronger metalinguistic awareness and explicit learning strategies, though they rarely achieve native-like accent

Cognitive Abilities

• Working memory capacity directly predicts vocabulary retention and the ability to process complex sentences in real time
• Analytical reasoning helps learners identify and apply grammatical patterns, especially in formal instruction settings
• Cognitive flexibility allows adaptation to unfamiliar linguistic structures and reduces interference from the native language

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Motivational Factors

Motivation determines not just whether someone learns, but how deeply they engage with the material. Self-determination theory distinguishes between motivation that comes from within versus motivation driven by external pressures.

Motivation Types

• Intrinsic motivation—learning driven by personal interest or enjoyment—produces deeper engagement and better long-term retention
• Integrative motivation (desire to connect with a culture) typically outperforms instrumental motivation (practical goals like career advancement)
• Extrinsic rewards can jumpstart learning but often fail to sustain effort once the reward is removed—a key limitation for classroom incentive systems

Personality Traits

• Extroversion correlates with SLA success because extroverts seek more social interaction and speaking practice
• Openness to experience predicts willingness to engage with unfamiliar cultural contexts and tolerate ambiguity in communication
• Language anxiety creates avoidance behaviors that reduce practice opportunities, directly impacting fluency development

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Environmental and Input Factors

Language learning requires raw material—exposure to the target language in sufficient quantity and quality. Input hypothesis suggests learners acquire language when they receive comprehensible input slightly beyond their current level.

Exposure to the Target Language

• Immersion environments provide naturalistic input through media, conversation, and cultural experiences, accelerating acquisition
• Quality of exposure matters as much as quantity—interactive, meaningful communication outperforms passive listening
• Contextual learning through exposure helps learners acquire pragmatic competence, the ability to use language appropriately in social situations

Formal Instruction

• Structured environments provide systematic exposure to grammar rules and vocabulary that learners might not encounter naturally
• Teacher expertise and curriculum design significantly impact whether instruction translates to actual communicative ability
• Explicit instruction works best when combined with opportunities for authentic practice—neither alone is sufficient

Social and Cultural Factors

• Supportive social networks provide both practice opportunities and emotional encouragement that sustain long-term effort
• Cultural attitudes toward the target language affect learners' willingness to identify with speakers of that language
• Acculturation—the degree to which learners adopt target culture behaviors—predicts ultimate attainment in naturalistic settings

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Cognitive and Strategic Factors

These factors reflect how learners process and manage the language input they receive. Effective learners don't just practice more—they practice smarter.

Learning Strategies

• Metacognitive strategies—planning, monitoring, and evaluating one's own learning—distinguish successful from unsuccessful learners
• Mnemonic devices like keyword methods and imagery aid vocabulary retention by creating memorable associations
• Social strategies such as seeking conversation partners and asking for clarification maximize interactive practice opportunities

Native Language Influence (L1 Transfer)

• Positive transfer occurs when L1 and L2 share features—Spanish speakers learning Italian benefit from similar grammar and vocabulary
• Negative transfer produces systematic errors when learners apply L1 rules inappropriately, such as word order mistakes
• Contrastive analysis helps learners anticipate interference patterns and consciously override L1 habits

Language Aptitude

• Phonetic coding ability—the capacity to distinguish and remember novel sounds—predicts pronunciation accuracy
• Grammatical sensitivity allows learners to recognize structural patterns without explicit instruction
• Aptitude tests like the MLAT (Modern Language Aptitude Test) predict learning rate but not ultimate attainment with sufficient time and effort

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Quick Reference Table

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Self-Check Questions

1. A student learning French achieves native-like pronunciation, while an adult learner with higher motivation does not. Which two factors best explain this difference, and how do they interact?

2. Compare integrative motivation and instrumental motivation. Which predicts better long-term outcomes, and why might this be the case from a psychological perspective?

3. An FRQ describes a learner who makes consistent word-order errors when speaking their second language. Which factor is most relevant, and what type of transfer does this represent?

4. How do metacognitive strategies differ from social strategies in language learning? Give an example of each and explain which aspect of acquisition each targets.

5. A researcher wants to predict which students in a language class will learn fastest. Should they measure language aptitude or motivation? Defend your answer, and explain what limitation exists for whichever factor you choose.