Argues that the late acquisition of the third-person singular agreement affix /-s/ in second-language learners of English is the result of a syntactic configuration that makes the ending appear ungrammatical to the learner of English while allowing agreement inflection to appear when the target language has a more robust agreement model, as in the…

Learners' grammaticality reactions emerge through cognitive processes and relate to the nature of the linguistic stimulus. Discussion of such metalinguistic judgments, particularly learners' tolerance of ill-formedness, attempts to clarify established perspectives, arguing that specific aspects of test strings may influence the saliency of certain…