“…It has long been noted that diffusing linguistic innovations morph as they spread (e.g., Britain, 2005Britain, , 2010Trudgill, 1986): (i) socially, by being differently sociologically embedded in the destination from in the source (witness, for example, the diffusion of the glottalization of /t/ from the Southeast of England, where it tends to be used most in informal styles and among working-class speakers, to Cardiff in Wales, where highest rates are found among middle-class women in more formal speech styles) (Mees & Collins, 1999); (ii) attitudinally, through evolutions in how innovations are evaluated; and (iii), importantly, linguistically, as innovations embed themselves into local grammars that often differ from one place to another. Labov (2007) showed how the diffusion of the complex New York system of short /a/ tensing to Northern New Jersey, Albany, Cincinnati, and New Orleans has led to subtle yet significant and, what is more, different changes in each.…”