ABSTRACT
This chapter proposes that there are both adaptive and non-adaptive aspects in the evolutionary process of language. It divides language into Language of Thought (LoT) and Language of Communication (LoC) on the basis of the assumption that case plays an important role in identifying thematic roles of nouns exclusively at LoC. The chapter presents the basis of the new dynamic model of language, it is argued that close attention should be paid to visibility in order to clarify the role of case, and that the diachronic view of the English language can provide new clues to solving the quirky subject issues. The study of language can be divided into the study of linguistic competence and the study of language use. The target of generative grammar is linguistic competence whereas language use is mainly dealt with in cognitive grammar, functional linguistics and sociolinguistics.
