Volume 113, Issue 5, May 2003
Index of content:
- SPEECH PRODUCTION 
113(2003); http://dx.doi.org/10.1121/1.1567279View Description Hide Description
This study examined the relationship of speech breathing to other elements of speech production. It was hypothesized that initiating speech from different lung volumes would have an effect on different elements of the acoustic output. It was postulated that effects may be brought about by mechanical interaction as well as a dispersion of effort to mechanically unlinked elements of speech production, such as articulatory behavior. To this end, selected acoustic variables were studied in eight young healthy women who initiated speech from low, typical, and high lung volume levels. The acoustic variables studied were selected because they have been shown to be sensitive indicators of speech production performance. It was found that with increasing lung volume initiation levels, average sound pressure level, average fundamental frequency, and declination rate of fundamental frequency increased. It was also observed that vowel space was significantly smaller during low lung volume initiation levels relative to typical lung volume initiation levels. Vowel space reduction is discussed relative to “gaining down.”
113(2003); http://dx.doi.org/10.1121/1.1562646View Description Hide Description
The tongue has been frequently characterized as being composed of several functionally independent articulators. The question of functional regionality within the tongue was examined by quantifying the strength of coupling among four different tongue locations across a large number of consonantal contexts and participants. Tongue behavior during swallowing was also described. Vertical displacements of pellets affixed to the tongue were extracted from the x-ray microbeam database. Forty-six participants recited 20 vowel-consonant-vowel (VCV) combinations and swallowed 10 ccs of water. Tongue-surface movement patterns were quantitatively described by computing the covariance between the vertical time-histories of all possible pellet pairs. Phonemic differentiation in vertical tongue motions was observed as coupling varied predictably across pellet pairs with place of articulation. Moreover, tongue displacements for speech and swallowing clustered into distinct groups based on their coupling profiles. Functional independence of anterior tongue regions was evidenced by a wide range of movement coupling relations between anterior tongue pellets. The strengths and weaknesses of the covariance-based analysis for characterizing tongue movement are considered.
113(2003); http://dx.doi.org/10.1121/1.1564013View Description Hide Description
This study presents EMA (electromagnetic articulography) data on articulation of the vowel /a/ at different prosodic boundaries in French. Three speakers of metropolitan French produced utterances containing the vowel /a/, preceded by /t/ and followed by one of six consonants /b d g f s ∫/ (three stops and three fricatives), with different prosodic boundaries intervening between the /a/ and the six different consonants. The prosodic boundaries investigated are the Utterance, the Intonational phrase, the Accentual phrase, and the Word. Data for the Tongue Tip, Tongue Body, and Jaw are presented. The articulatory data presented here were recorded at the same time as the acoustic data presented in Tabain [J. Acoust. Soc. Am. 113, 516–531 (2003)]. Analyses show that there is a strong effect on peak displacement of the vowel according to the prosodic hierarchy, with the stronger prosodic boundaries inducing a much lower Tongue Body and Jaw position than the weaker prosodic boundaries. Durations of both the opening movement into and the closing movement out of the vowel are also affected. Peak velocity of the articulatory movements is also examined, and, contrary to results for phrase-final lengthening, it is found that peak velocity of the opening movement into the vowel tends to increase with the higher prosodic boundaries, together with the increased magnitude of the movement between the consonant and the vowel. Results for the closing movement out of the vowel and into the consonant are not so clear. Since one speaker shows evidence of utterance-level articulatory declension, it is suggested that the competing constraints of articulatory declension and prosodic effects might explain some previous results on phrase-final lengthening.
Using links between speech perception and speech production to evaluate different acoustic metrics: A preliminary report113(2003); http://dx.doi.org/10.1121/1.1567280View Description Hide Description
This paper examines whether correlations between speech perception and speech production exist, and, if so, whether they might provide a way of evaluating different acoustic metrics. The cues listeners use for many phonemic distinctions are not known, often because many different acoustic cues are highly correlated with one another, making it difficult to distinguish among them. Perception-production correlations may provide a new means of doing so. In the present paper, correlations were examined between acoustic measures taken on listeners’ perceptual prototypes for a given speech category and on their average production of members of that category. Significant correlations were found for VOT among stop consonants, and for spectral peaks (but not centroids or skewness) for voiceless fricatives. These results suggest that correlations between speech perception and production may provide a methodology for evaluating different proposed acoustic metrics.