How different is prototype change?
Over the last twenty-five years a consensus has developed among cognitive linguists that semantic change (as viewed within polysemous radial categories or sets) includes the modification of meaning in ways that cause some element(s) of the category to become more or less central (or prototypical) over time. Among other changes, the prototype itself may change, with an earlier central instance becoming more peripheral (or disappearing entirely) and being replaced by another, related meaning. This paper addresses changes in prototypicality, through an exploration of the degree to which change in the most central meaning of a radially configured set is the same as or different from change in other aspects of the set. We examine examples from phonology, the lexicon, and grammar and conclude that the outcomes of prototype change are different from other changes in set configuration, but that the processes by which these central instances of a linguistic unit change are the same as other, non-prototype modifications in meaning.