William J. Hardcastle

Speech production and speech modelling

Section 1: Physiological Framework for the Speech Production Process.- Organization of the Articulatory System: Peripheral Mechanisms and Central Coordination.- Respiratory Activity in Speech.- Acquisition of Speech Production: the Achievement of Segmental Independence.- Section 2: Coarticuiation and Other Connected Speech Processes.- Segmental Reduction in Connected Speech in German: Phonological Facts and Phonetic Explanations.- V-C-V Lingual Coarticuiation and its Spatiotemporal Domain.- Section 3: Models of Articulatory-Acoustic Relationships.- Compensatory Articulation During Speech Evidence from the Analysis and Synthesis of Vocal-tract Shapes Using an Articulatory Model.- Articulatory Synthesis.- Articulatory-Acoustic Relationships in Fricative Consonants.- Articulatory-Acoustic-Phonetic Relations and Modelling, Regions and Modes.- Evidence for Nonlinear Sound Production Mechanisms in the Vocal Tract.- Section 4: Theories and Models of Articulatory Organization and Timing.- Testing Theories of Speech Production: Implications of Some Detailed Analyses of Variable Articulatory Data.- Speech as Audible Gestures.- Articulatory Perspectives of Speech Organization.- Speech Motor Timing.- The Acoustic and Physiologic Characteristics of Neurologically Impaired Speech Movements.- Explaining Phonetic Variation: A Sketch of the H and H Theory.

Coarticulation : theory, data and techniques

List of figures List of tables List of contributors Acknowledgments Introduction William J. Hardcastle and Nigel Hewlett Part I. Theories and Models: 1. The origin of coarticulation Barbara Kuhnert and Francis Nolan 2. Coarticulation models in recent speech production theories Edda Farnetani and Daniel Recasens Part II. Research Results: Components of the Motor System for Speech: 3. Velopharyngeal coarticulation Michel Chafcouloff and Alain Marchal 4. Lingual coarticulation Daniel Recasens 5. Laryngeal coarticulation Philip Hoole, Christer Gobl and Ailbhe Ni Chasaide 6. Labial coarticulation Edda Farnetani 7. Lip and jaw coarticulation Janet Fletcher and Jonathan Harrington Part III. Wider Perspectives: 8. Cross-language studies: relating language-particular coarticulation patterns to other language-particular facts Sharon Manuel 9. Implications for phonological theory Mary Beckman Part IV. Instrumental Techniques: 10. Palatography Fiona Gibbon and Katerina Nicolaidis 11. Imaging techniques Maureen Stone 12. Electromagnetic articulography Philip Hoole and Noel Nguyen 13. Electromyography William J. Hardcastle 14. Transducers for investigating velopharyngeal function Michel Chafcouloff 15. Techniques for investigating laryngeal articulation Philip Hoole, Christer Gobl and Ailbhe Ni Chasaide 16. Acoustic analysis Daniel Recasens References Index.

New developments in electropalatography: A state-of-the-art report

Recent developments in Electropalatography (EPG) as a technique for investigating spatio-temporal details of tongue contacts with the hard palate in both normal and pathological speech are reviewed. Details of hardware and software design for the Reading EPG systems are described and illustrated, including a new multichannel data acquisition system developed as part of an IBM-Reading University collaborative research project.

Extensions to the International Phonetic Alphabet for the transcription of atypical speech

This paper introduces and illustrates the Extensions to the International Phonetic Alphabet (IPA) that have been recommended for the narrow transcription of disordered speech. The relationship between these Extensions and previous suggestions for transcribing atypical speech made by the Working Party for the Phonetic Representation of Disordered Speech (PRDS) is described. By including the transcription of aspects of connected speech such as voice quality, rate and intensity, and by permitting uncertainty in transcription to be indicated, the International Phonetic Association has sanctioned significant developments in transcription conventions that will be of use to many people concerned with the narrow transcription of speech.

Some phonetic and syntactic constraints on lingual coarticulation during /kl/ sequences

Abstract The effects of vowel context, juncture and rate of utterance on anticipatory co-articulation in /kl/ sequences were studied with the technique of electropalatography, which records details of the location and timing of tongue contacts with the hard palate during speech. Four subjects produced test items in which a variety of different prosodically-marked syntactic junctures fell between the /k/ and /l/, at two different rates of utterance and in two different vowel environments. Co-articulation was measured as the time interval from the release of the /k/ closure to the onset of anterior tongue movement for the /l/. Subjects showed considerable variation in co-articulatory patterns used in most of the test items but there was a clear tendency towards more extensive co-articulation in the fast rate of utterance. Major syntactic boundaries seemed to have little effect on the degree of co-articulation except in the slow rate of utterance, where for three of the four subjects the onset of the anterior movement for /l/ was consistently delayed. Vowel context had little consistent effect in either fast or slow rates.

A Re-Evaluation of the Nature of Speech Errors in Normal and Disordered Speakers

It is well known that speech errors in normal and aphasic speakers share cer-tain key characteristics. Traditionally, many of these errors are regarded as serial misorderings of abstract phonological segments, which maintain the phonetic well-formedness of the utterance. The current paper brings together the results of several articulatory studies undertaken independently for both subject popula-tions. These show that, in an error, instead of one segment substituting for another, two segments are often produced simultaneously even though only one segment may be heard. Such data pose problems for current models of speech production by suggesting that the commonly assumed dichotomous distinction between phonological and phonetic errors may not be tenable in the current form or may even be altogether redundant.

Deviant articulation in a cleft palate child following late repair of the hard palate: A description and remediation procedure using electropalatography (EPG)

Older children with repaired cleft palates who have unresolved speech difficulties present the clinician with a particular challenge, since they do not respond readily to conventional therapy techniques (Noordhoff, Kuo, Wang, Huang and Witzel, 1987). This study describes the use of EPG in the investigation and remediation of a 13-year-old cleft palate boy, who presented with an apparently intractable posterior pattern of articulation. This subject also had received delayed hard palate surgery, which took place at the age of 11 years. EPG printouts of palato-lingual patterns provided information that both confirmed perceptual judgements and also revealed details of articulatory movements that could not be detected from the acoustic signal. A treatment procedure using EPG as a visual feedback device was successful in establishing correct tongue placements. Possible relevant aetiological factors relating to the development of posterior tongue placements are discussed.

A Comparative Investigation of Coarticulation in Fricatives: Electropalatographic, Electromagnetic, and Acoustic Data

The principal aim of this investigation was to compare coarticulatory effects at different levels of the speech production system, in order to gain insight into the relations between the different levels. To this end, the relative magnitudes of carryover and anticipatory coarticulation with adjacent vowels were measured at the midpoints of the two lingual fricatives /s/ and /∫/ in two speakers each of English, French, and German. Linguopalatal contact patterns derived from electropalatographic recordings were compared with an analysis of the acoustic output. The results indicated, firstly, that mismatches between articulatory and acoustic results are not uncommon. Secondly, and more surprisingly, while there was no difference in the overall magnitude of coarticulatory effects for /s/ and /∫/, not all speakers showed a predominance of the same coarticulatory direction on both fricatives; this complicated the observed tendency for the predominance of carryover coarticulation to be greater in German and English than in French. Two speakers were retested using comparative analyses of electropalatography and electromagnetic articulography. These two procedures gave a closely parallel picture of lingual coarticulatory regularities (while complementing each other in terms of characterizing articulation). The implications of these results for identifying language-specific coarticulatory regularities are discussed.

Articulatory and perceptual factors in /l/ vocalisations in English

In several dialects of English notably in the southern part of Britain (but excluding Wales), a velarised or “dark” allophone of /l/ occurs syllable-finally, and post-vocalically in syllable-final consonant clusters (Wells 1982; Gimson 1980). A variant of this velarised [l], typically associated with Cockney, but increasingly admitted as a feature of South-Eastern Urban English, is a “vowelised” or vocalised form realised as a non-syllabic back vocoid (approximately [Y] or a rounded equivalent [o] or [ʊ] (Wells 1982; Hughes and Trudgill 1986)). Thus “milk” may be realised variously as [mIlk], [mIYk], [mIok] or [mIʊk].

Parallel electropalatographic and acoustic measures of fricatives

This work explores methods of parameterizing parallel palatographic and acoustic descriptions of the fricatives /s/ and 1/2. The immediate aim of the parameterization was to facilitate elucidation of the relationships between the two sets of data. The longer-term, clinically-oriented aim was to determine the feasibility of using this approach to converge on acoustic parameters sensitive to systematic articulatory variation.The ways in which the values of the different palatographic and acoustic parameters reflect the influence of the experimental variables (speaker, fricative phoneme, vocalic context and position in word) are compared and discussed. Generally, the two sets of parameters appeared comparable in sensitivity. In addition, the attempt was made to predict values of the acoustic parameters from the measured values of the EPG parameters. The prediction was also successful enough to warrant applying the approach in future to more extensive material.