Дыбыс өзгерісінің таралуы және тіл біліміндегі заңдылықтар

Lexical diffusion is the hypothesis that a sound change is an abrupt change that spreads gradually across the words in a language to which it is applicable. It contrasts with the Neogrammarian view that a sound change results from phonetically conditioned articulatory drift acting uniformly on all applicable words, which implies that sound changes are regular, with exceptions attributed to analogy and dialect borrowing. Similar views were expressed by Romance dialectologists in the late 19th century but were reformulated and renamed by William Wang and coworkers studying varieties of Chinese in the 1960s and the 1970s. William Labov found evidence for both processes but argued that they operate at different levels.

A key assumption of historical linguistics is that sound change is regular. The principle was summarized by the Neogrammarians in the late 19th century in the slogan "sound laws suffer no exceptions" and forms the basis of the comparative method of reconstruction and the tree model of linguistic evolution. Inspired by the Uniformitarian Principle of geology, Neogrammarians such as Hermann Paul described regularity as a consequence of the operation of sound change as an imperceptible articulatory drift conditioned by the phonetic environment. Leonard Bloomfield later summarized this view:

He summarized the mechanism as "phonemes change". Despite the unequivocal form in which these slogans are often quoted, the Neogrammarians admitted two exceptions to regular sound change: analogy and dialect borrowing.