| This thesis challenges the claim that syntactic change should be modeled in terms of adjustments in the probability distribution of competing grammars (Kroch 1989; Yang 2000). Building on work of Boersma and Hayes (2001) and Bresnan et al. (2001), I propose a novel framework for modeling syntactic change. In this approach, grammars are conceived of as constraint rankings on a continuous scale of real numbers. Further, in the process of speaking or hearing (i.e., at any evaluation point) the rank of each constraint is slightly perturbed by adding a random value drawn from a normal distribution. This perturbation of constraint ranking leads to intraspeaker variation and, consequently, defines a probability distribution over outputs from the grammar for a given input, where the input is the meaning of an utterance or the speech stream. Given this model of linguistic competence, syntactic change is reflected by adjustments in constraint strength along a continuous scale.; Two case studies on syntactic change in early English form the empirical core of this thesis: the gradual decline of right-headed structures and change in the syntax of subjects. These case studies draw on data from secondary sources, as well as novel evidence from parsed corpora of Old and Middle English. The analyses proposed capture generalizations about English clause structure change discussed in earlier work, with empirical gains. Certain logically possible but unattested word orders are predicted to be absent. Further, a theory embedded in this framework allows one to give a unified analysis of change in the syntax of different subject types in early English, accounting for why subject pronouns adopted the syntax of full noun phrase subjects in Middle English.; The case studies also highlight several important properties of the grammatical model advocated for in this thesis. First, the model contains a nondeterministic, noncategorical, and quantitative component that captures intratextual variation. Second, the steady quantitative rise in the rate of use of an innovation is reflected by gradual adjustments of constraint strength. Third, the model accounts directly for the observation that categorical phenomena at one stage of a language show up as statistical preferences at another. |
