Which statement best reflects language development milestones and the concept of a critical period for language acquisition?

Which statement best reflects language development milestones and the concept of a critical period for language acquisition?

• A. Babbling begins around 3 months and two-word phrases by year 2; the critical period ends around adolescence; social interaction has no impact.
• B. Language development is entirely environmental and not influenced by social interaction.
• C. Babbling begins around 7-10 months; first words around year 1; two-word phrases by year 2; the critical period extends roughly to puberty; social interaction is essential for acquiring grammar and vocabulary.
• D. Language ability is determined by genetics alone, with no environmental impact.

Answer: (C)

Language development follows a clear sequence and depends on the brain’s heightened plasticity early in life, with social interaction playing a crucial role in shaping both grammar and vocabulary. Babbling typically starts around 7–10 months, single words emerge around the first birthday, and two‑word combinations appear by about age 2. The idea of a critical period suggests this early window is especially important for language learning, with some researchers noting that the period extends roughly to puberty, though learning later is still possible with effort. Social interaction provides the input, feedback, and joint attention that are essential for acquiring grammar and expanding vocabulary. This option fits best because it aligns with the observed milestones and the role of social experience in language development, plus the notion of a broad, early critical period. Other statements conflict with well-supported ideas: some give incorrect timing or dismiss environmental and social influences, or attribute language outcomes solely to genetics.

Language development follows a clear sequence and depends on the brain’s heightened plasticity early in life, with social interaction playing a crucial role in shaping both grammar and vocabulary. Babbling typically starts around 7–10 months, single words emerge around the first birthday, and two‑word combinations appear by about age 2. The idea of a critical period suggests this early window is especially important for language learning, with some researchers noting that the period extends roughly to puberty, though learning later is still possible with effort. Social interaction provides the input, feedback, and joint attention that are essential for acquiring grammar and expanding vocabulary.

This option fits best because it aligns with the observed milestones and the role of social experience in language development, plus the notion of a broad, early critical period. Other statements conflict with well-supported ideas: some give incorrect timing or dismiss environmental and social influences, or attribute language outcomes solely to genetics.