Volume 55, Issue 3

The purpose of this study is to explore the contribution of higher frequencies to fricative consonant classification in Australian English. The spectral range above 10 kHz is analysed in an attempt to provide better classifications of the dental and the labiodental fricatives. A comparison is made between real-word data and data from a controlled-word context. Although results for the controlled-word context suggest that spectral information above 10 kHz may be of use in classifying [f] correctly, these results are not repeated for the real-word data. Moreover, classification of [f] and [q] using only the information above 10 kHz yields quite poor results. It is also shown that the results for the voiced dental and labiodental fricatives are not as promising as those for their voiceless counterparts.

Velar consonants often show an elliptical pattern of tongue movement in symmetrical vowel contexts, but the forces responsible for this remain unclear. We here consider the role of overpressure (increased intraoral air pressure) behind the constriction by examining how movement patterns are modified when speakers change from an egressive to ingressive airstream. Tongue movement and respiratory data were obtained from 3 speakers. The two airstream conditions were additionally combined with two levels of speech volume. The results showed consistent reductions in forward tongue movement during consonant closure in the ingressive conditions. Thus, overpressure behind the constriction may partly determine preferred movement patterns, but it cannot be the only influence since forward movement during closure is usually reduced but not eliminated in ingressive speech.

This paper examines the effect of contrastive emphasis on the amount of vertical jaw displacement, as measured from X-ray microbeam data, for 3 American English speakers. Jaw opening in short utterances with one word emphasized (in initial, middle, and final positions) was compared with that of similar utterances with no words emphasized. The results suggest that emphasis involves not only a significant increase in jaw opening on the word emphasized but also possibly a reduction of jaw opening on the word following emphasis. Emphasis in addition may affect the amount of jaw opening of the utterance as a whole, in terms of a decrement in jaw opening on all the remaining words in the utterance following the emphasized word. The relationship between jaw opening and hierarchical levels of prosodic structure is tentatively discussed.