Band 54, Heft 3-4

Many studies have shown that listeners process speech in a rate-dependent manner, altering the location of phonetic category boundaries in accord with the acoustic consequences of a change in rate during speech production. In a recent series of papers that focused on a voicing contrast, we reported that the perceptual adjustment for rate is not limited to the region of the category boundary, but extends to well within the category, producing a change in which stimuli are perceived to be the best category exemplars. In the current paper, we provide evidence for the generality of this effect by showing analogous results for a /b/––/w/ contrast, specified by transition duration. The implications of these findings for models of rate-dependent processing are discussed.

Previous work has indicated that there may be a positive relationship between the duration and extent of inspiration and the length of an upcoming utterance. However, none of that work has uniquely implied a role of planning. We attempted to avoid some of the alternative explanations by forcing subjects to utter single sentences ranging in length from 5 to 82 syllables (mean of 27), after inspiring fully and then expiring down to a set level before uttering the sentence. For all 3 subjects, there was a significant positive relationship between utterance length and inspiration duration, regardless of whether inspiration was measured physiologically or acoustically. The 2 subjects with the higher correlations in the articulatory measures also expended air more quickly during the shorter sentences than longer ones, while the other subject had no correlation with exhalation rate. Complexity of the sentence, calculated as the number of clauses in the sentence, did not affect inspiration duration. The individual differences need further investigation, but there is a positive correlation between the duration of the sentence to be said and the inspiration before it when the speaker is required to read sentences while using only one breath.

Early babbling has been characterized as being fundamentally a mandibular oscillation: the infant’s repeated lowering and raising of its mandible yields a perceived contrast between consonants produced in a closed vocal tract configuration and vowels produced with an open tract. We wondered whether babblers produce rhythmic mandibular oscillations without phonation and, if so, whether there might be a relationship between such ‘jaw wags’ and early speech. We report two studies: the first is a longitudinal, observational study of 14 infants, some of whom were hearing and some Deaf. Seven infants (3 hearing, 3 Deaf, and 1 hearing-impaired) produced numerous speech-like, rhythmic jaw wags without phonation; sometimes jaw wags formed a single utterance with phonated babbling. Most jaw wags reported here were produced when these infants were ages 8–13 months. The second study, a survey of 90 parents of 4- to 10-month-old hearing infants, suggests that silent babbles may be a widespread phenomenon of early speech development.

In order to evaluate hypotheses regarding production constraints on final consonants in babbling, 721 utterance-final consonants produced by 6 infants in consonant-vowel-consonant (CVC) syllables were examined and compared with the preceding consonant in the CVC. Consistent with earlier studies, major patterns were observed for each of the three main consonantal properties – place and manner of articulation and voicing. These patterns included a strong tendency for final consonants to repeat the place of articulation of nonfinal consonants and a tendency for relatively more fricative, nasal and voiceless consonants to occur in final position than in nonfinal position. The high frequency with which final consonants shared place of articulation with the preceding consonant was considered to reflect ‘frame dominance’ or the tendency of a relatively constant mandibular cycle (the frame) to determine the structure of utterances with very little contribution from other active articulators. The manner and voicing effects were attributed to an overall terminal energy decrease in the vocal production system.

The intent of the present study is to investigate the information for place of articulation provided by locus equations, using Moroccan speakers of Modern Standard Arabic. Locus equations are straight-line regression function fits to co-ordinates derived by relating onsets of F₂ transitions of different vowels to their corresponding steady states. Ten subjects produced CVCVC(VC) tokens, the first consonant of each was one of the following list: (/f/, /b/, / bx/, /s/, /sx/, /d/, /dx/, /t/, /tx/, /σ/, /h/, /χ). Each initial consonant was followed by one of the six vowels (/i/, /æ/, /u/, /i:/, /æ:/, /u:/). The present study attempted to explore to what extent locus equations can distinguish between different consonants varying in place and manner of articulation. The findings are of two kinds. On the one hand, locus equations do not reflect certain place-of-articulation distinctions when many consonants varying both in place and manner of articulation are taken into consideration. On the other hand, locus equations are successful in distinguishing place between pharyngealized and non-pharyngealized consonants. Pharyngealized consonants (/bx, dx, sx, tx/) emerged as a totally distinct class, having the flattest locus equation slopes of all consonants.