Journal of Memory and Language

Second-language (L2) acquisition is generally thought to be constrained by maturational factors that circumscribe a critical period for nativelike attainment. Consistent with the maturational view are age effects among learners who begin L2 acquisition prior to, but not after, closure of the putative critical period. Also favoring the maturational account is the scarcity of late L2 learners at asymptote who perform like natives, and weak effects of native language–target language pairings. With Korean and Chinese learners of English, the experimental study of Johnson and Newport (1989) yielded just these types of evidence. Some subsequent studies do not support the critical period account of L2 acquisition constraints, however. Accordingly, we undertook a replication of Johnson and Newport (1989), using the exact methods and materials of the original experiment, and a sample of Spanish natives (n = 61). In keeping with recent research, L2 attainment negatively correlates with age of learning even if learning commences after the presumed end of the critical period. We also find modest evidence of nativelike attainment among late learners. Our data further suggest that the outcome of L2 acquisition may depend on L1–L2 pairings and L2 use. © 2001 Academic Press