How Languages Are Learned

“My students can score 100% on a written grammar test on the Present Perfect, but ten minutes later in a free speaking activity, they revert to ‘Yesterday I have gone to the shop’. Why can’t they output what I just taught them?” This classic dilemma plagues teachers every day. The myth that explicit grammar rule memorization directly transforms into fluent, spontaneous speech remains one of the most persistent misconceptions in language education.

Core Theory & Terminology

Understanding Second Language Acquisition (SLA) requires examining the major theoretical paradigms that have shaped modern methodology, as synthesized by Patsy Lightbown and Nina Spada (How Languages Are Learned):

1. Behaviorism vs. Innatism vs. Interactionism

• Behaviorism (B.F. Skinner): Viewed language learning as habit formation through imitation, repetition, and reinforcement. This theoretical foundation directly birthed the Audio-Lingual Method.
• Innatism (Noam Chomsky): Posited that humans possess an innate Language Acquisition Device (LAD) containing Universal Grammar (UG), arguing that environmental input alone cannot account for the child’s complex linguistic knowledge (the “Poverty of the Stimulus”).
• Interactionism (Vygotsky, Long, Swain): Asserts that language acquisition occurs through social interaction. Michael Long’s Interaction Hypothesis highlights the role of modified input and negotiation of meaning during communication breakdown.

2. Stephen Krashen’s Monitor Model (5 Hypotheses)

Stephen Krashen formulated five foundational hypotheses that sparked decades of SLA debate:

1. The Acquisition-Learning Hypothesis: Distinguishes between subconscious acquisition (picking up language naturally through meaningful communication) and conscious learning (formal study of grammatical rules). Krashen argued these two systems are completely separate (the “No-Interface” position).
2. The Input Hypothesis (i + 1): States that acquisition occurs only when the learner receives comprehensible input containing structures slightly beyond their current level of competence (i + 1).
3. The Monitor Hypothesis: Proposes that consciously learned grammar functions only as an editor or “monitor” to polish utterances initiated by the acquired system, provided the learner has time, focuses on form, and knows the rule.
4. The Natural Order Hypothesis: Asserts that grammatical structures are acquired in a predictable, developmental sequence regardless of the order in which they are explicitly taught.
5. The Affective Filter Hypothesis: Suggests that emotional variables—such as high anxiety, low self-confidence, or lack of motivation—act as a mental barrier preventing comprehensible input from reaching the LAD.

3. Interlanguage & Developmental Stages

Coined by Larry Selinker, Interlanguage refers to the independent, rule-governed linguistic system developed by L2 learners on their path toward the target language. Interlanguage is systematic, dynamic, and prone to fossilization—where linguistic forms cease to develop despite continued exposure.

In the classroom

For teachers in training, SLA theory provides the rationale behind observed lesson criteria:

• In Formal Lesson Planning: Objectives should account for developmental readiness. As Manfred Pienemann’s Teachability Hypothesis demonstrates, teaching a structure that is far beyond a learner’s current interlanguage stage will not result in immediate acquisition.
• On Observed Lessons: Teacher educators evaluate how effectively candidates scaffold input. Over-explaining abstract metalanguage often raises the affective filter, whereas providing multimodal context (images, realia, gestures) makes input comprehensible without overwhelming learners.
• Mentor Feedback: Observers frequently remind trainees that student errors are not evidence of teaching failure, but vital evidence of an evolving interlanguage system actively testing hypotheses.

Practical Classroom Application

Scaffolding Comprehensible Input (i + 1)

To operationalize i + 1 in daily practice, use this 4-step input framework:

1. Contextualize First: Before introducing a target text or audio, build background knowledge (schema) using visuals, concept questions, or personal anecdotes.
2. Provide Meaningful Redundancy: Rephrase key ideas using synonyms, visual aids, and clear stress rather than speaking unnaturally slow.
3. Incorporate Noticing Tasks: Use textual enhancement (bolding, color-coding) to help learners “notice” target features in authentic input before asking them to produce them.
4. Lower the Affective Filter: Use low-stakes pairwork prior to open-class checking to allow risk-taking without fear of immediate public error.

Reflection & Further Reading

Reflective Question

In what ways does your current lesson staging rely on the assumption that explicit learning directly converts into spontaneous output? How can you increase opportunities for natural acquisition?

Key Reference Areas

• Lightbown, P., & Spada, N. — How Languages Are Learned (Chapters 3 & 4).
• Thornbury, S. — An A-Z of ELT (Entries: Interlanguage, Noticing, Monitor Model).
• Scrivener, J. — Learning Teaching (Chapter 2: “Learning Language”).