The Logical Problem of Language Change

Abstract

In this chapter, we consider the problem of language change. Linguists have to explain not only how languages are learned (a problem we investigated in the previous chapter), but also how and why they have evolved in certain trajectories. While the language learning problem has concentrated on the behavior of the individual child, and how it acquires a particular grammar (from a class of grammars g), we consider, in this chapter, a population of such child learners, and investigate the emergent, global, population characteristics of the linguistic community over several generations. We argue that language change is the logical consequence of specific assumptions about grammatical theories, and learning paradigms. In particular, we are able to transform the parameterized theories, and memoryless algorithms of the previous chapter into grammatical dynamical systems, whose evolution depicts the evolving linguistic composition of the population. We investigate the linguistic, and computational consequences of this fact. From a more programmatic perspective, we lay a possible logical framework for the scientific study of historical linguistics, and introduce thereby, a formal diachronic criterion for adequacy of linguistic theories.