Open Access

Eric Fuß

• The present chapter outlines a research program for historical linguistics based on the idea that the object of the formal study of language change should be defined as grammar change, that is, a set of discrete differences between the target grammar and the grammar acquired by the learner (Hale 2007). This approach is shown to offer new answers to some classical problems of historical linguistics (Weinreich et al. 1968), concerning, specifically, the actuation of changes and the observation that the transition from one historical state to another proceeds gradually. It is argued that learners are highly sensitive to small fluctuations in the linguistic input they receive, making change inevitable, while the impression of gradualness is linked to independent factors (diffusion in a speech community, and grammar competition). Special attention is paid to grammaticalization phenomena, which offer insights into the nature of functional categories, the building blocks of clause structure.