Why does the shtyle spread? Street prestige boosts the diffusion of urban vernacular features

In this article, we investigate social meaning as a determinant of linguistic diffusion by confronting laboratory and corpus data of Citetaal, a multi-ethnolect that has spread across Flanders. In a speaker evaluation experiment, we found that Citetaal was upgraded on 'streetwise dynamism', even by respondents unfamiliar with its migrant origin. From this, we conclude that it is Citetaal's third-order indexicality, pruned of ethnic associations, which carries the diffusion. To determine the relative importance of streetwise cool vis-a-vis other predictors, we studied the diffusion across Twitter of the principal Citetaal shibboleth (/s/ palatalisation). As a production proxy for streetwise cool, we included expressive compensation strategies such as lengthening (verrry), which turned out to be among the main predictors of the Citetaal form. We argue that social meaning is a major change determinant, and that Twitter is the optimum source to track both a diffusion and the factors, including social meaning, which drive it.