Current theories place very mild constraints on possible diachronic changes, something at odds with the trivial observation that actual, “language change” represents a tiny fraction of the variation made a priori available by Universal Grammar. Much recent work in diachronic syntax has actually been guided by the aim of describing changes (e.g., parameter resetting), rather than by concerns of genuine explanation. Here I suggest a radically different viewpoint (the Inertial, Theory of diachronic syntax), namely, that syntactic change not provably due to interference should not occur at all as a primitive-that is, unless forced by changes in the phonology, the semantics, or the lexicon, perhaps ultimately by interface or grammar-external pressures, in line with the minimalist enterprise in synchronic linguistics. I concentrate on a single case, the etymology of Modern French chez , showing howthe proposed approach attains a high degree of explanatory adequacy.

Superficially postverbal subjects of free inversion languages such as, Italian are argued to be able to meet two distinct structural analyses: they may occupy either a VP-internal position, as more traditionally assumed, or a higher (preverbal and, actually, left-peripheral) position, with the remnant of the clause crossing leftward over them by dislocation or focus movement. These are all and only the possibilities expected under recent restrictive theories of phrase structure, like the one advocated by Kayne (1994), and are exactly those empirically realized. Evidence for this conclusion is based primarily on the, (existential/generic) interpretation of bare nouns and overt indefinites and is reinforced by extraction considerations. The whole analysis, based on the interpretation of Romance indefinites, is likely to support some version of Diesing's (1992) Mapping Hypothesis even more strongly than previous types of evidence did, including the original data from Germanic languages.