The categorical and gradient phonology of variable t-deletion in English

The purpose of this paper is to unpack some fundamental concepts that have been appearing more often in the literature recently, and show, through the use of a specific example, what sort of methodology may be appropriate to use in addressing these concepts empirically. The concepts are categoricality vs. gradience and variability vs. invariance; the example is -t,d deletion in American English (henceforth referred to as t-deletion); and the methodology advocated here involves the statistical analysis of the physical output of speech production. The central lesson of this paper, then, is that researchers interested in the above concepts, whether theoretical phonologists, sociolinguists, or psycholinguists, should prepare themselves to deal with the analysis of physical data.