Critical period effects in second language learning: the influence of maturational state on the acquisition of English as a second language.
Level 3 - non-randomized controlled study
Non-randomized cross-sectional comparative cohort study evaluating proficiency by age of arrival
PubMed 2920538 · doi:10.1016/0010-0285(89)90003-0
What was done
Evaluated English grammatical proficiency in 46 native Korean or Chinese speakers who immigrated to the United States between the ages of 3 and 39 and had resided there for 3 to 26 years. Participants completed a grammaticality judgment task assessing a wide variety of English syntactic structures. Performance was analyzed using correlational and t-test analyses comparing earlier versus later arrivals while evaluating potential confounding factors such as duration of exposure, motivation, self-consciousness, and American identification.
What was found
Test performance correlated linearly with age of arrival for participants who arrived prior to puberty. For post-pubescent arrivals, performance was lower, highly variable, and unrelated to age of arrival. The advantage for earlier arrivals appeared across all grammatical structures tested. Specific numerical test scores, correlation values, and statistical significance thresholds were not reported in the abstract.
Why it matters
This paper provides key empirical support for the critical period hypothesis extending to second language acquisition, suggesting that maturational state up to puberty constrains ultimate attainment in grammar.
Limits
The sample size is relatively small (n = 46) and limited to native Korean and Chinese speakers acquiring English. The cross-sectional design infers developmental limits from retrospective cohorts rather than longitudinal follow-up, and specific quantitative metrics are omitted from the abstract.
Cited by
- contradicts The critical period for robust passive developmental neuroplasticity (such as learning multiple languages without an accent) typically closes around age 25.