The task in this book was to present a theory of syntax from the communication-andcognition perspective. As stated in section 1.4, the general skeleton of the theory is drawn from RRG, and many parts of the theory are elaborations on basic RRG concepts, e.g. the layered structure of the clause, semantic macroroles, potential focus domain, pragmatic pivots, juncture and nexus. But the content of many of the analyses integrate ideas from a variety of theories and individuals, e.g. Rijkhoff's theory of noun phrase structure from FG, the notion of constructional template adapted from ConG, Lambrecht's theory of information structure, Pustejovsky's theory of nominal qualia, the pragmatic analysis of pronominalization of Kuno, Bolinger and Bickerton, and Jackendoff's ideas about reflexivization, to name a few.

Of the issues raised in chapter 1, one of the most important issues, and for some linguists, the most important issue, is language acquisition. In section 1.3.2 we briefly mentioned work by a number of linguists, psycholinguists and psychologists on this topic from the communication-and-cognition perspective, and in this final section, we will look at the implications of the syntactic analyses we have presented for theoretical questions in acquisition and child language.

The first step is to clarify the foundational issue, namely, assumptions about the nature of the human cognitive endowment regarding language. Chomsky has always been very clear that for him the essential features of the grammars of human languages are part of a species-specific, genetically determined biological organ of language; indeed, he now claims (Chomsky 1995) that the basic syntax of all languages is the same and that all cross-linguistic variation is due to lexical differences.