Patterns of pre-nasal allophony across dialects of English: A multi-corpus study of the /ɪ/-/ɛ/ contrast

We present a study of pre-nasal allophony across a variety of English dialects from North America and the UK in order to investigate the degree to which pre-nasal allophony behaves categorically or gradiently in English. We focus on the contrast between /ɪ/ and /ɛ/, which undergoes allophonic merger in the Southern US and has a marginal F1/F2 contrast in Scottish English. There are two attested types of pre-nasal allophony in English: pre-nasal coarticulation and pre-nasal merger. Both types of allophony are predicted to have the effect of bringing /ɪ/ and /ɛ/ closer together in F1/F2 space. We compare the amount of overlap between /ɪ/ and /ɛ/ in pre-nasal contexts to the pre-oral "baseline" overlap and ask whether dialects and individual speakers fall along a gradient with respect to pre-nasal vs. pre-oral overlap. We find that dialects fall roughly into two groups, but there is evidence of dialects falling in between the two groups. These findings support a "hybrid" view of pre-nasal allophony, in which behavior is roughly categorical, but dialects can exhibit intermediate, gradient behavior. Within dialects, interspeaker variation shows more evidence for gradient behavior, although only two dialects exhibit what appears to be a full gradient in pre-nasal allophony.