Nature, nurture and universal grammar

In just a few years, children achieve a stable state of linguistic competen ce, making them effectively adults with respect to: understanding novel sen tences, discerning relations of paraphrase and entailment, acceptability ju dgments, etc. One familiar account of the language acquisition process trea ts it as an induction problem of the sort that arises in any domain where t he knowledge achieved is logically underdetermined by experience. This view highlights the 'cues' that are available in the input to children, as well as children's skills in extracting relevant information and forming genera lizations on the basis of the data they receive. Nativists, on the other ha nd, contend that language-learners project beyond their experience in ways that the input does not even suggest. Instead of viewing language acquisiti on as a special case of theory induction, nativists posit a Universal Gramm ar, with innately specified linguistic principles of grammar formation. The 'nature versus nurture' debate continues, as various ''poverty of stimulus '' arguments are challenged or supported by developments in linguistic theo ry and by findings from psycholinguistic investigations of child language. In light of some recent challenges to nativism, we rehearse old poverty-of stimulus arguments, and supplement them by drawing on more recent work in l inguistic theory and studies of child language.