Yes, we still need Universal Grammar

In a recent paper [Lidz, J., Gleitman, H., & Gleitman, L. (2003). Understanding how input matters: Verb learning and the footprint of universal grammar. Cognition, 87, 151–178], we provided cross-linguistic evidence in favor of the following linked assertions: (i) Verb argument structure is a correlate of verb meaning; (ii) However, argument structure is not directly available to learners as a cue for reconstructing verb meaning, owing to the complexity of form-meaning mappings within and across languages; (iii) A major correlate of argument-structure, namely, noun phrase number, is statistically available on the surface in all languages, and serves as a quasi-universal derivative cue to the meanings of verbs; (iv) this cue is privileged, in the sense that it is used early and selectively by learners, despite within- and cross-language differences in its availability. Goldberg [Goldberg, A. (2004). But do we need Universal Grammar? Comment on Lidz, Gleitman and Gleitman 2003. Cognition] suggests that this cue is not linguistic, that it is too sicklied oʹer with exceptions and provisos to be useful to learners, and that conversational conspiracies can in any case serve as the alternative theoretical framework for a theory of predicate learning, and language acquisition more generally. In the present reply, we review and further explicate our original position, to wit: A large part of any generative grammar is a formal statement of the complex alignments between predicate-argument structures and the surface forms (linear strings of words) of sentences. Because the several rules for alignment interact, the surface outcomes reveal individual systematicities only abstractly. Therefore, learning would be impossible if infants could not analyze probabilistically available patterns to recover their principled linguistic sources. This statistics-based discovery procedure is in certain relevant regards specific to language learning. Finally, we argue that while pragmatics and theory of mind properties in learner and tutor necessarily frame language acquisition, that these have not been shown—and probably cannot be shown—to be sufficient to this computational problem.