Perceptions of /a/ fronting Across Two Michigan Dialects 237was found here that listeners from Detroit, Michigan were sensitive to NCCS-
inÀ uenced vowels—as revealed in individual talkers’ sentence productions—
while listeners from Ishpeming, Michigan were not. When trying to account
for this pattern of results, one is drawn to the notion of speech community.
Speech community is typically de¿ ned as a group of speakers united on the
basis of their shared language characteristics, as well as regional and social
attributes (Wolfram and Schilling-Estes, 1998).
The speech communities of Ishpeming, in the Upper Peninsula, and
Detroit, in Lower Michigan, differ from each other substantially in regard to
their adoption of NCCS. The dialectally diverse Detroit-area populations have
been exposed to a number of NCCS pronunciation features, and the middle
Figure 9.9 Psychometric functions for the LM respondents. The upper panel shows
responses for sentence carriers produced by Talker UP; the lower panel
shows responses for sentence carriers produced by Talker LM.