Lexical tectonics: Mapping structural change in patterns of lexification

Abstract Whether it is based on philological data or on reconstruction, historical linguistics formulates etymological hypotheses that entail changes both in form and in meaning. Semantic change can be understood as a change in “patterns of lexification”, i. e., correspondences between forms and senses. Thus a polysemous word, which once lexified senses s1–s2–s3, evolves so it later encodes s2–s3–s4. Meanings that used to be colexified are now dislexified, and vice versa. Leaning on empirical data from Romance and from Oceanic, this study outlines a general model of historical lexicology, and identifies five types of structural innovations in the lexicon: split, merger, competition, shift, and relexification. The theoretical discussion is made easier by using a visual approach to structural change, in the form of diachronic maps. Semantic maps have already proven useful to represent synchronic patterns of lexification, outlining each language’s emic categories against a grid of etic senses. The same principle can be profitably used when analysing lexification patterns in diachrony: lexical change is then viewed as the reconfiguration of sense clusters in a semantic space. Maps help us visualize the “lexical tectonics” at play as words evolve over time, gradually shifting their meaning, gaining or losing semantic territory, colliding with each other, or disappearing forever.