Preliminary study of articulatory reorganisation of fricative consonants following osteotomy.

Patients who undergo osteotomy experience a radical change in the skeletal relationship between the mandible and maxilla and as yet little is known about how this affects speech articulation. This study investigated the extent to which articulatory placement for the lingual consonant /s/ changed following surgery. Using the technique of electropalatography and acoustic analysis, patients' productions of fricative sounds were recorded before and after osteotomy. Five patients were investigated, 3 with mandibular prognathism and 2 with maxillary protrusion. Results showed that there were significant changes in articulatory placement after the operation, and that these were correlated with an acoustic measure (CPF). The direction of change could be predicted on the basis of the type of operation undergone, and these changes were maintained 6 months post-operatively. The implications of the findings are discussed.

Phonetic and phonological aspects of English affricate production in children with speech disorders.

In this paper we consider phonetic and phonological aspects of the English voiceless affricate /t integral of/ as it is realised by children with developmental speech disorders. The speakers described in the study have normal /t/ but disordered /integral of/ and /t integral of/. Using electropalatography (Reading EPG), we compare the stop and fricative phases of /t integral of/ to independent /t/ and /integral of/. This comparison shows that the place of articulation of /t integral of/ can be predicted from that of independent /integral of/. There is a strict requirement for the affricate's stop release to be homorganic with its fricative phase, irrespective of the place of articulation of independent /t/. Sometimes, there is also an observable coronal gesture during the stop phase of a dorsal affricate indicating the influence of independent /t/. This is predicted by phonological theories in which the affricate is related to both /t/ and /integral of/ but not by theories in which the affricate is merely the stop counterpart go /integral of/.

New developments in EPG3 software.

New developments in EPG3 software are described including: a three-dimensional display of the electrodes on the palate in the form of a wire frame representation; a facility for annotating EPG3 files; and a new data management system. Recent methods of EPG data reduction are also described, including numerical indices for representing tongue-palate contact profiles. A new clinical version of the Reading EPG system, EPG4, is introduced.

Cross-linguistic study of lateral misarticulation using electropalatography.

This paper reports on some preliminary aspects of a collaborative cross-linguistic study of normal and disordered Japanese and British English speech. The investigation compares lateralised productions of parallel s which are abnormal in the two languages. EPG and acoustic recordings were made of four Japanese and four British subjects. The EPG patterns were classified according to certain criteria, such as the presence or absence of complete constriction between the tongue and the hard palate, and the area and location of this contact. Findings revealed that lateralised articulations varied between individual speakers, but that Japanese and English productions were broadly similar. Acoustically, misarticulations in both languages were characterised by a lower frequency of peak energy than would be expected in normal productions.

ACCOR: instrumentation and database for cross-language study of coarticulation.

An unavoidable problem in speech technology, particularly in the development of robust automatic speech recognition systems, is the extreme variability in the acoustic attributes of segments. Segments are highly sensitive to context and bear little resemblance to their intrinsic characteristics manifested when they are uttered in isolation. However, the problem can become tractable if we model the linguistic and physiological aspects of coarticulatory processes, the main source of systemic variability at the segmental level.

Respiratory kinematics in speakers with cerebellar disease.

The respiratory abilities of a group of 12 speech disordered subjects with cerebellar disease were assessed using both spirometric and kinematic techniques and compared to those of a group of 12 non-neurologically impaired controls matched for age and gender. Results of the spirometric assessment showed that although all of the cerebellar-diseased subjects had normal total lung capacities, almost half had vital capacities below normal limits. All except 1 of the cerebellar-diseased subjects exhibited irregularities in their chest wall movements while performing sustained vowel and syllable repetition tasks. Over half of the cerebellar-diseased subjects also displayed similar irregularities when reading and conversing. The same irregularities were not present in the chest wall movements exhibited by the control subjects suggesting that their presence was caused by the cerebellar disease. Results are discussed in terms of the effects of cerebellar disease on neuromuscular function.

Visual display of tongue-palate contact: electropalatography in the assessment and remediation of speech disorders.

The technique of electropalatography (EPG) records the location and timing of tongue contacts with the hard palate during continuous speech. Recent developments in hardware and software design of the Reading electropalatograph are described and applications of the technique in assessment and remediation of a variety of speech disorders are outlined. In assessment, it is shown that EPG can provide insights into possible origins of auditorily perceived errors, and case descriptions illustrate how this information can lead to a more rationalised approach to treatment. In therapy, the provision of real-time visual feedback of tongue movement can be effective in the remediation of certain types of intractable speech problems. Finally, the importance of techniques such as EPG in the objective evaluation of treatment procedures is discussed in the light of the increasing demand for accountability within the speech therapy service.

An instrumental phonetic study of lingual activity in articulation-disordered children.

Traditional auditory-based assessment procedures for diagnosing articulation disorders are limited in that they provide no direct information on activities of the speech organs. In this study electropalatography (EPG) was used to obtain details of tongue contacts with the hard palate in 4 articulation-disordered children, 2 of whom had been categorized as dysarthric. Their lingual-palatal contact patterns during four repetitions of word lists containing lingual consonants in different phonetic environments, were compared with each other and with a group of normal speakers. EPG provided relevant diagnostic information in that all 4 experimental subjects showed patterns that differed from the normals in both spatial configuration and variability. The nature of their distorted patterns allowed a tentative diagnosis of 2 of the children as verbal dyspraxic.