Subglottal resonances and distinctive features

This paper addresses the phonetic basis of the distinctive feature [±back]. The second subglottal resonance (Sg2) is known to fall near the boundary between [−back] and [+back] vowels, and it has been claimed that Sg2 actually defines this distinction. In this paper, new evidence in support of this hypothesis is presented from 14 adult and 9 child speakers of American English, in which accelerometer recordings of subglottal acoustics were made simultaneously with speech recordings. The first three formants and the second subglottal resonance were measured, and both Sg2 and F3-3.5 bark were tested as boundaries between front and back vowels in the F2-dimension. It was found that Sg2 provides a reliable boundary between front and back vowels for children of all ages, as well as for adults, whereas F3-3.5 bark provides a similarly reliable boundary only for older children and adults. Furthermore, a study of connected speech in one adult male indicated that Sg2 forms a boundary between front and back vowels in such speech as well as in laboratory speech. Some implications for quantal theory and landmark theory are discussed, as well as the possibility that subglottal resonances might play a broader role in speech production.