Linguapalatal Contact Patterns Research Articles

Labial-Lingual Double Articulations in Speakers with Cleft Palate

Labial-lingual double articulations (LLDAs) are speech errors involving simultaneous valving at the lips and in the linguapalatal region. This study investigates the frequency of LLDAs occurring for /p/, /b/, and /m/ targets and describes the linguapalatal contact patterns involved in these abnormal articulations. A retrospective study involving analysis of articulatory data from all speakers with cleft palate recorded at a research center over a 10-year period. Twenty-seven speakers aged 5 to 62 years (median 11 years) with compensatory speech errors associated with repaired cleft palate. The lingual component of LLDAs was identified using electropalatography (EPG). EPG data were recorded simultaneously with acoustic data. Fifteen bilabial targets (/p/, /b/, /m/) per participant were analyzed. LLDAs were identified in cases where complete linguapalatal constriction (as observed from EPG data) occurred throughout the closure phase of bilabial targets. The labial component of LLDAs was identified from clinical observations of the speakers made during productions of bilabial targets. Three speakers (11%) frequently produced LLDAs for bilabial targets. The configuration of tongue-palate contacts involved in the lingual component of the LLDAs differed in each of the three speakers: one speaker had velar constriction, another had alveolar constriction, and the third had simultaneous alveolar-velar constriction. LLDAs did not similarly affect bilabial targets in the three speakers. One speaker produced LLDAs for /p/ and /b/ targets only. Another produced LLDAs for all /m/ targets but inconsistently for /p/ and /b/ targets. The third speaker produced LLDAs for all /b/ targets but inconsistently for /p/ and /m/ targets. LLDAs occurred in a minority of speakers investigated. Nevertheless, it is argued that it is important to identify LLDAs for clinical decision making and for research purposes. The results from this study add to current knowledge about abnormal articulations in cleft palate speech, but further research is needed into the precise timing of lip and tongue-palate closures and into the airflow and acoustic characteristics of LLDAs.

Labial-Lingual Double Articulations in Speakers With Cleft Palate

Abstract Objective: Labial-lingual double articulations (LLDAs) are speech errors involving simultaneous valving at the lips and in the linguapalatal region. This study investigates the frequency of LLDAs occurring for /p/, /b/, and /m/ targets and describes the linguapalatal contact patterns involved in these abnormal articulations. Design: A retrospective study involving analysis of articulatory data from all speakers with cleft palate recorded at a research center over a 10-year period. Participants: Twenty-seven speakers aged 5 to 62 years (median 11 years) with compensatory speech errors associated with repaired cleft palate. Measures: The lingual component of LLDAs was identified using electropalatography (EPG). EPG data were recorded simultaneously with acoustic data. Fifteen bilabial targets (/p/, /b/, /m/) per participant were analyzed. LLDAs were identified in cases where complete linguapalatal constriction (as observed from EPG data) occurred throughout the closure phase of bilabial targets. Th...

A study of voicing and context effects upon consonant linguapalatal contact patterns

Consonant linguapalatal contacts were studied using electropalatography (EPG) by recording 10 normal, English-speaking adults repeating CV syllables (C = /t,d,k,g,s,z,∫, 3 ,t∫,d 3 ,r,l/, V = /i,a,u/). Contact patterns were examined for total number of electrodes contacted and for consonant specific parameters. Comparisons were made across vowel environments and voicing contrasts. For alveolar and velar stops, the voiced cognates had greater anterior/posterior (A/P) midline lengths of contact while lateral contacts remained relatively the same. This suggested lateral tongue contact was primarily used for creating a seal to prevent air escape while the central regions responded to the voicing differences. Vowel anticipatory effects resulted in the greatest number of contacts in the /i/ context and the fewest in the /a/ context. For the sibilants, groove widths were dictated by voicing characteristics (narrower for voiced cognates) and the grooves were unaffected by vowel context. Vowel context effects were seen for lateral widths of contact only. Vowel context effects were found to affect both length and width of contact for the /r/ whereas with the /1/ only the lateral A/P lengths of contact were affected. Results are discussed in terms of physiological constraints upon the tongue in producing the various consonants, the three dimensional nature of the tongue, and the ability of the tongue components (e.g., tip, blade, dorsum) to function relatively independently.

Comparing Abilities of Children With Profound Hearing Impairments to Learn Consonants Using Electropalatography or Traditional Aural.Oral Techniques

Two groups of nine children with profound hearing impairments and low intelligibility were taught to produce the consonants /t,d,k,g,s,z,S/ using either electropalatographic (palatometry) or traditional aural-oral techniques. Testing was completed pre-, immediately post-, and 6 months post-treatment by examining productions of CV syllables (V = /i,a/) using electropalatography-determined linguapalatal contacts and listener identifications. Intelligibility was also measured using the CID Picture Speech Intelligibility Evaluation (SPINE) test. Both groups improved their consonant productions as a result of 26 50-minute sessions. Sessions were given twice daily over 3- to 4-week training periods. Immediately post-treatment, the electropalatography-trained subjects produced better consonants as measured by linguapalatal contact patterns and listener identifications. The linguapalatal-contact patterns learned by the electropalatography-trained group better matched normal speaker productions than did those of the traditionally trained group. Both groups showed equal improvement for both post-treatment conditions when tested with the CID SPINE test. Although further research is needed, the results of this study suggest that electropalatographic techniques are, at least, equal alternatives to traditional aural-oral speech training techniques for speakers with profound hearing impairments.

Lingua-palatal coarticulation by deaf and normal-hearing speakers

Recent research suggests that deaf speakers often exhibit context-dependent changes in speech articulation [for example, Mahshie etal., ASHA 32 (10), 183 (1990)]. However the coarticulatory patterns of deaf speakers are not always comparable to those of normal-hearing speakers. Furthermore, it is likely that deaf individuals exhibit differences among themselves in both the nature and extent of coarticulation–differences that may affect intelligibility. The purpose of the present study was to examine and compare lingua-palatal coarticulation evidenced by normal-hearing speakers and by deaf speakers differing in overall speech intelligibility. Three normal-hearing subjects, one intelligible deaf subject, and one semi-intelligible deaf subject produced multiple iterations of bisyllabic and trisyllabic words. Test words contained the lingua-alveolar target segments /t/ or /n/ followed by either the neutral vowel /schwa/ (e.g., ‘‘tana’’) or the velar consonant /k/ (e.g., ‘‘tancat’’). Palatometric measures were used to compare lingua-palatal contact patterns during production of the target consonants in the vowel and consonant contexts. Results showed that the intelligible deaf speaker, like the three normal-hearing subjects, exhibited context-dependent changes in articulation of the target segments, while the semi-intelligible deaf subject showed little evidence of anticipatory coarticulation. Possible motor organization strategies employed by the deaf subjects will be discussed.

Esophageal speaker articulation of /s,z/: A dynamic palatometric assessment

Esophageal talker linguapalatal contact patterns and durations during /s/ and /z/ productions were examined using dynamic palometry instrumentation. It was found that sibilant groove narrowing is a physiologic compensation for a reduced air supply in esophageal speech. The place of esophageal /s, z/ articulation was on the anterior portion of the alveolar ridge as seen in normal speakers. Average medial groove width for esophageal /s/ was narrower than the 5–7-mm groove characteristics of normal speakers. Groove widths averaged 3 mm for /s/ and 4 mm for /z/. Systematic changes in groove widths across speech sounds, syllable position, and vowel context were also observed. Use of a narrower lingual groove was interpreted as a significant articulatory maneuver to meter out a limited intraoral air supply and effect more normal fricative durations.

Articulatory Function After Resection of the Tongue and Floor of the Mouth

Linguapalatal contact patterns and the time course of changes in contacts during utterances of/asa, ata, a sa, aca/ were measured using electropalatography (EPG). The relations between these data and perceptual scores in 17 glossectomized patients after various surgical methods were examined. The linguapalatal contact patterns produced during perceptually less distorted sounds varied with the place and manner of articulation. Patterns having very few contacts or a posterior groove produced more distorted /s/ sounds; however, types of EPG patterns producing less distorted /s/ sounds were relatively frequent. Distortion of the and /c/ sounds was less often produced by variation of the EPG patterns, whereas /t/ sounds were most frequently judged to be highly distorted. Patterns that showed complete constriction along the dental arch or constriction on the anterior portion of the hard palate, as well as rapid release for plosion by the tongue tip, produced less distorted /t/ sounds. The results revealed that glossectomized patients often evidenced defective stop sounds. It was concluded that mobility rather than volume of the residual tongue is required to produce less distorted stops.

Teaching Consonants to Profoundly Hearing-Impaired Speakers Using Palatometry

Five profoundly hearing-impaired children were taught the consonants /t,d,k,g,s,z integral of/ using palatometry. Changes in linguapalatal contact patterns and listener perceptions showed significant improvement in the place and manner of consonants produced by all subjects. Velar stops were as easily and accurately learned as alveolar stops. Distinctive sibilants were also found by the end of training. Sounds not previously present in a subject's phonetic repetoire were learned more accurately than those present but inaccurate prior to therapy. Voicing errors persisted. Two of the subjects showed evidence of newly established, unsolicited coarticulated movements. The results indicated that visual articulatory modeling and feedback of linguapalatal contact patterns is an effective means of teaching consonants and improving speech intelligibility.

Recognition of words from palatometric displays

This experiment was designed to explore articulatory perception at the phonetic gesture level. It was hypothesized that with relatively brief experience individuals could learn to identify words from video displays of linguapalatal contact patterns, that such learning will reveal general visual articulatory perception rules, and that both vowels and consonants will be differentiated by their contact patterns. Movements to and from articulatory positions, the number of syllables in a word, place and extent of linguapalatal contact, and specific articulatory gestures such as sibilant grooving and stop occlusion patterns were found to be used in word differentiation and recognition.

Effects of variation in speaking rate, loudness, and vocalic context on linguapalatal contact patterns in Hindi sibilants

A 96-channel electropalatograph was used to monitor normal, fast, and loud production of sibilants in the nonsense words /bisiÝb/, /basáb/, /busúb/ and /bišíb/, /bašáb/, /bušúb/ spoken in a carrier phrase by a native speaker of Hindi. Results showed the following. (1) Groove width (GW, in number of uncontacted sensors×2 mm) was considerably narrower for /s/ (4.64 mm) than /š/ (9.26 mm). (2) GW for /s/ decreased from normal to fast to loud speech; just the opposite was true for /š/. (3) For both /s/ and /š/, GW was narrower in the context of /a/ than /i/ or /u/; in the latter two, it was narrower in the /u/ context. (4) Anterior-posterior location (APL) of the groove (in number of contacted rows) occurred generally at the second and third rows for /s/ and the fourth and fifth rows for /š/. Consequently, the center of the groove for /s/ was 4 mm anterior to that for /š/ (i.e., the difference in the number of rows×2 mm). (5) APL of the groove for /s/ was more anterior in loud than normal or fast speech; in the latter two, it was more anterior in normal speech. (6) Groove APL for /s/ was more anterior in the context of /a/ than /i/ or /u/; in the latter two, it was more anterior in the context of /i/. (7) For /š/, groove APL was more posterior in fast than normal or loud speech; in the latter two, it was more posterior in loud speech. (8) Groove APL for /š/ shifted more posteriorly from /i/ to /a/ to /u/ context. [Work supported by NIH Grant NS20572.]

Compensating for a bite block in /s/ and /t/ production: Palatographic, acoustic, and perceptual data

Electropalatography was used to monitor linguapalatal contact patterns in /s/ and /t/. Talkers often compensated incompletely for a bite block, both immediately after its insertion (sample B1) and after 10 min of practice (sample B2). Significant differences in the number of sensors contacted were noted between normal and bite-block samples for both /s/ and /t/. Differences in length of constriction in /t/, and the A-P location and width of the groove in /s/ were also noted. The two native English subjects compensated better than three Arabic subjects, perhaps because English /s/ and /t/ are formed more posteriorily and with a smaller contact area than their Arabic counterparts. A significant correlation existed between the area and A-P location of linguapalatal contact. All five subjects formed a groove for /s/ in sample B2, but two often did not produce /t/ with complete constriction. This suggests a groove is critical for /s/, but complete constriction is not critical for /t/. The contact patterns in sample B2 more closely resembled normal speech than those in sample B1 in some instances, while in other instances the reverse was true. The conclusion that subjects sometimes overcompensated in sample B2 was supported by the results of detailed acoustic and perceptual analyses for one subject. Taken together, the results suggest that compensation for a bite block is not instantaneous, and that specific parameter values may be encoded in central phonetic representations.

Articulatory and acoustic properties of /s, z/ consonants produced by esophageal speakers

The objective of the present study was to identify specific articulatory maneuvers and their acoustic consequences during production of /s, z/ consonants by esophageal speakers. The consonants were embedded in CVC syllables (V = i, ae, u/) in a sentence. Information on linguapalatal contact, lip and mandible position, and speech output were collected from three fluent male alaryngeal esophageal speakers who had received no radical neck dissection. Dimensions of the anterior tongue constriction and their variations were extrapolated from the linguapalatal contact patterns and subjects' dental models. Spectra of frication noises in the frequency range up to 8 Khz were characterized by a model with a set of resonances and antiresonances. The results will be discussed with respect to known functions of speech physiology and acoustics. [Supported by NIH grant NS‐11852‐02 and by NIH grant RR‐5349 awarded to the first author.]

Articulatory characteristics of fluent esophageal speakers for selected english consonants

Linguapalatal contact characteristics and lip and mandible coordination of three fluent alaryngeal esophageal speakers were examined during the production of English consonants /p, t, k, s, b, d, g, z/ in CVC syllables (V = /æ/) embedded in a sentence “_____ is a word.” Pseudopalates with 96 electrodes were fabricated for each subject. Small light reflecting beads were placed on the lips and on cantilevers attached to mandibular and maxillary teeth to determine lip and mandible movements. Information on linguapalatal contact, lip and mandible positions, and voice spectrum were collected every 10 msec with the PAGIS instrumental system. Linguapalatal contact patterns were analyzed with reference to those of normal speakers in terms of place and duration of contact. The contact patterns were related to lip and mandible positions for the criterion CVC syllables. The results will be discussed with respect to known functions of speech physiology. [Supported by NIH grant NS-11852-02 and by NIH grant RR-5349 awarded to the first author.]