L2 Journal: An electronic refereed journal for foreign and second language educators

This article examines the role of input in two contrasting theories of language acquisition: nativist (UG) theory and the usage-based (emergentist) approach. Although extensive treatments of input are available for first language acquisition (cf. Gathercole & Hoff, 2007), such research rarely incorporates findings from second language acquisition. Accordingly, this paper examines a range of linguistic phenomena from both first and second language contexts (e.g., yes-no question formation, constraints on want-to con¬traction) in order to illustrate how each theory might explain their acquisition. The discussion of input presented here addresses various constructs, including the problem of the poverty of the stimulus, the lack of negative evidence, the role of indirect (missing) evidence, recovery from overgeneralization, and frequency effects. The article concludes with a reappraisal of the poverty of the stimulus problem in SLA from a usage-based perspective.