Tongue/palate contact for the production of /s/ and /z/

Productions of /s/ and /z/ by ten adult speakers were investigated using the electropalatograph (EPG). The participants, ten speech researchers who spoke English as their first language, recorded productions of /s/ and /z/ in nonsense and real words. The maximum contact frame was used as the point of reference to compare tongue/palate contact for each production. Each speaker had alveolar contact, lateral bracing and most had a midline groove for both /s/ and /z/; however, the array of contacted electrodes was unique for each speaker. The groove widths and lengths ranged from 0–3 electrodes. There was significantly greater alveolar tongue/palate contact for /z/ compared to /s/ in word‐initial position, but not in word‐final position for the following measures: alveolar palatal contact, medial groove width, medial groove length. However, when measures of total palate contact and centre of gravity were considered, there was a complex interaction between the phonemes /s/ and /z/, coarticulation with the vowel, word position, and word context (real and nonsense words).     

Electropalatographic specification of Croatian fricatives /s/ and /z/

Electropalatographic specification of alveolar fricatives in Croatian is aimed at providing speech therapists with normative data about the range of acceptable productions of /s/ and /z/ in adult speakers of Croatian. Four variables were analysed: place of articulation, total contact, groove width and hold phase duration. Intra- and inter-speaker variability for each variable was analysed. Lingual palatal cues for voicing difference were also quantified and discussed. Results show that Croatian /s/ and /z/ are alveolar and not dental as previously reported. The comparison between the voiced and the voiceless fricative shows that durational measures provide the best differentiation. The voiceless counterpart is significantly longer. The difference between voiced and voiceless is also found in the total contact, with /z/ having more contact in the anterior four rows of electrodes, while /s/ has more contact in the posterior four rows of electrodes. This difference is also reflected in the anterior and the posterior groove widths. Possibilities of using these results as normative data for the diagnosis and treatment of atypical articulation of /s/ and /z/ are discussed.     

Speech-language pathologists' knowledge of tongue/palate contact for consonants

Speech-language pathologists (SLPs) rely on knowledge of tongue placement to assess and provide intervention. A total of 175 SLPs who worked with children with speech sound disorders (SSDs) drew coronal diagrams of tongue/palate contact for 24 English consonants. Comparisons were made between their responses and typical English-speaking adults' contact established by electropalatography (EPG). SLPs were most accurate for consonants with no contact (h, p, f), then velar consonants (g, k, ng). The remaining consonants were rarely accurate (from most to least accurate: l, t, r, z, n, sh, s, zh, y, v, th(voiceless), d, m, b, w, th(voiced), ch, j). SLPs demonstrated good knowledge of contact along the midline, but poor knowledge of contact along lateral margins of the palate. Importantly, SLPs did not show awareness of: lateral bracing ('horseshoe' contact) for alveolar consonants (t, d, n, s, z); the groove for s, z, sh, zh; or posterior lateral contact for most other consonants. Accuracy was not influenced by the following: length of time as SLP, location of SLP training, location of current workplace, proportion of caseload with SSD or childhood apraxia of speech, amount of time spent reading, or exposure to EPG. Awareness of coronal tongue placement for consonant production needs targeting in SLP education.     

Speech–language pathologists’ knowledge of tongue/palate contact for consonants

Speech–language pathologists (SLPs) rely on knowledge of tongue placement to assess and provide intervention. A total of 175 SLPs who worked with children with speech sound disorders (SSDs) drew coronal diagrams of tongue/palate contact for 24 English consonants. Comparisons were made between their responses and typical English-speaking adults’ contact established by electropalatography (EPG). SLPs were most accurate for consonants with no contact (h, p, f), then velar consonants (g, k, ng). The remaining consonants were rarely accurate (from most to least accurate: l, t, r, z, n, sh, s, zh, y, v, th(voiceless), d, m, b, w, th(voiced), ch, j). SLPs demonstrated good knowledge of contact along the midline, but poor knowledge of contact along lateral margins of the palate. Importantly, SLPs did not show awareness of: lateral bracing (‘horseshoe’ contact) for alveolar consonants (t, d, n, s, z); the groove for s, z, sh, zh; or posterior lateral contact for most other consonants. Accuracy was not influenced by the following: length of time as SLP, location of SLP training, location of current workplace, proportion of caseload with SSD or childhood apraxia of speech, amount of time spent reading, or exposure to EPG. Awareness of coronal tongue placement for consonant production needs targeting in SLP education.     

Sibilant production in Hebrew-speaking adults: Apical versus laminal

The Hebrew IPA charts describe the sibilants /s, z/ as ‘alveolar fricatives’, where the place of articulation on the palate is the alveolar ridge. The point of constriction on the tongue is not defined – apical (tip) or laminal (blade). Usually, speech and language pathologists (SLPs) use the apical placement in Hebrew articulation therapy. Some researchers and SLPs suggested that acceptable /s, z/ could be also produced with the laminal placement (i.e. the tip of the tongue approximating the lower incisors). The present study focused at the clinical level, attempting to determine the prevalence of these alternative points of constriction on the tongue for /s/ and /z/ in three different samples of Hebrew-speaking young adults (total n = 242), with typical articulation. Around 60% of the participants reported using the laminal position, regardless of several speaker-related variables (e.g. tongue-thrust swallowing, gender). Laminal production was more common in /s/ (than /z/), coda (than onset) position of the sibilant, mono- (than di-) syllabic words, and with non-alveolar (than alveolar) adjacent consonants. Experiment 3 revealed no acoustical differences between apical and laminal productions of /s/ and of /z/. From a clinical perspective, we wish to raise the awareness of SLPs to the prevalence of the two placements when treating Hebrew speakers, noting that tongue placements were highly correlated across sibilants. Finally, we recommend adopting a client-centred practice, where tongue placement is matched to the client. We further recommend selecting targets for intervention based on our findings, and separating between different prosodic positions in treatment.     

Australian adults' production of /n/: an EPG investigation

Images of tongue/palate contact for the nasal phoneme /n/ were created using the electropalatograph (EPG). Seven typical Australian adults with no history of hearing or communication difficulty produced syllables containing /n/ paired with five vowels. The majority of productions were symmetrical had contact with the alveolar ridge, and lateral bracing along the sides of the palate; however, there were notable exceptions. There was a wide range of inter- and intra-participant variation in the visual representations of the maximum point of contact as well as in measures of total palate contact (TPC) and centre of gravity (COG). It is suggested that when describing acceptable production of /n/ a range of tongue/palate contact patterns are provided.     

Tongue-palate contact of perceptually acceptable alveolar stops

Increased tongue–palate contact for perceptually acceptable alveolar stops has been observed in children with speech sound disorders (SSD). This is a retrospective study that further investigated this issue by using quantitative measures to compare the target alveolar stops /t/, /d/ and /n/ produced in words by nine children with SSD (20 tokens of /t/, 13 /d/ and 11 /n/) to those produced by eight typical children (32 /t/, 24 /d/ and 16 /n/). The results showed that children with SSD had significantly higher percent contact than the typical children for target /t/; the difference for /d/ and /n/ was not significant. Children with SSD generally showed more contact in the posterior central area of the palate than the typical children. The results suggested that broader tongue–palate contact is a general articulatory feature for children with SSD and its differential effect on error perception might be related to the different articulatory requirements.     

Articulatory placement for /t/, /d/, /k/ and /g/ targets in school age children with speech disorders associated with cleft palate

This study used electropalatography (EPG) to identify place of articulation for lingual plosive targets /t/, /d/, /k/ and /g/ in the speech of 15 school age children with repaired cleft palate. Perceptual judgements indicated that all children had correct velar placement for /k/, /g/ targets, but /t/, /d/ targets were produced as errors involving palatalization or velar placement. An EPG classification scheme identified alveolar, palatal and velar placement. Articulations involving contact in alveolar and velar regions simultaneously were identified as alveolar velar double articulations (AVDAs). The classification revealed that AVDAs were relatively frequent, with 28% of alveolar and 12% of velar targets affected, and ten out of the 15 children produced one or more of these abnormal articulations. The majority of children had variable placements, with alveolar more variable than velar targets. The positive finding from the EPG data revealed that most children with perceptual errors for /t/, /d/ were able to make closure in the alveolar region during at least some of their attempts to articulate these targets. It is argued that appropriate analysis and interpretation of EPG data provide clinically relevant information about tongue placement in cleft palate speech.     

Articulatory placement for /t/, /d/, /k/ and /g/ targets in school age children with speech disorders associated with cleft palate

This study used electropalatography (EPG) to identify place of articulation for lingual plosive targets /t/, /d/, /k/ and /g/ in the speech of 15 school age children with repaired cleft palate. Perceptual judgements indicated that all children had correct velar placement for /k/, /g/ targets, but /t/, /d/ targets were produced as errors involving palatalization or velar placement. An EPG classification scheme identified alveolar, palatal and velar placement. Articulations involving contact in alveolar and velar regions simultaneously were identified as alveolar velar double articulations (AVDAs). The classification revealed that AVDAs were relatively frequent, with 28% of alveolar and 12% of velar targets affected, and ten out of the 15 children produced one or more of these abnormal articulations. The majority of children had variable placements, with alveolar more variable than velar targets. The positive finding from the EPG data revealed that most children with perceptual errors for /t/, /d/ were able to make closure in the alveolar region during at least some of their attempts to articulate these targets. It is argued that appropriate analysis and interpretation of EPG data provide clinically relevant information about tongue placement in cleft palate speech.     

Lateral bracing of the tongue during the onset phase of alveolar stops: An EPG study

Although raising the sides of the tongue to form a seal with the palate and upper teeth – lateral bracing – plays a key role in controlling airflow direction, providing overall tongue stability and building up oral pressure during alveolar consonant production, details of this articulatory gesture remain poorly understood. This study examined the dynamics of lateral bracing during the onset of alveolar stops /t/, /d/, /n/ produced by15 typical English-speaking adults using electropalatography. Percent tongue palate contact in the lateral regions over a 150-ms period from the preceding schwa to stop closure was measured. Rapid rising of the sides of the tongue from the back towards the front during the 50-ms period before closure was observed, with oral stops showing significantly more contact than nasal stops. This feature corresponds to well-documented formant transitions detectable from acoustic analysis. Possible explanations for increased contact for oral stops and clinical implications are discussed.     

Aspects of spatio‐temporal variability during consonant production by Greek speakers with hearing impairment

This paper investigates spatio‐temporal variability during the production of the lingual consonants /t, k, s, x, n, l, ?/ by four Greek speakers with profound hearing impairment and with differences in the intelligibility of their speech. It examines important factors that have been documented to influence intelligibility, i.e. durational variability, articulatory (token‐to‐token) variability, and coarticulatory patterns. The technique of electropalatography was used to record tongue‐palate contact patterns during consonant production in order to examine differences in articulatory variability among speakers and in V‐to‐C coarticulatory effects. The study reports durational differences in consonant production between speakers with hearing impairment and normal hearing and investigates the relationship between token‐to‐token variability in tongue‐palate contact patterns and duration. The results indicate a negative relationship between duration and variability, i.e. as segmental duration decreases there is an increase in variability in tongue‐palate contact patterns. Significant speaker‐dependent differences in duration, articulatory variability and coarticulatory patterns are reported and are discussed in relation to differences in intelligibility among the speakers with hearing impairment.     

Lexical/semantic processing in dorsal left inferior frontal gyrus

Previous studies have not determined whether the dorsal left inferior frontal gyrus has a lexical or semantic function. This study conducted an event-related functional MRI experiment to explore its function using Japanese words and nonsense words in a syllable counting task. The word task activated a dorsal area (BA6/44) and a ventral area (BA45/47) more extensively than did the nonsense word task. The results indicate that the dorsal area also has lexical or semantic functions, despite that it has been related to phonological processing from studies using written stimuli. The more extensive activation by the word task might result from the same level of effort during phonological processing of Japanese words and nonsense words.     

Laterality effects in voice recognition

Dichotic voice recognition was assessed in three groups of 16 right-handed subjects by a procedure in which a sample voice was presented binaurally and the subject was required to indicate which of two dichotically-presented voices was that of the sample speaker. Consonants, vowels, nonsense syllables, and words were used as speech stimuli. Significant right- ear superiority occurred for subjects who responded by naming the ear in which the matching speaker was heard and for subjects who circled the stimulus spoken by the matching speaker on a response sheet, but no significant ear difference was found for subjects who orally repeated the utterance of the matching speaker. Overall accuracy of recognition tended to be greatest with words and nonsense syllables and least with vowels and consonants as speech stimuli. There was no significant interaction between ears and speech stimuli. It was concluded that the right-ear superiority in voice recognition by ear naming and visual choice responses is associated with left-hemisphere dominance for voice recognition.     

The influence of sublexical and lexical representations on the processing of spoken words in English

Previous research suggests that sublexical and lexical representations are involved in spoken word recognition. The current experiment examined when sublexical and lexical representations are used in the processing of real words in English. The same set of words varying in phonotactic probability/neighbourhood density was presented in three different versions of a same-different matching task: (1) mostly real words as filler items, (2) an equal number of words and nonsense words as filler items and (3) mostly nonsense words as filler items. The results showed that lexical representations were used in version 1 of the same-different matching task to process the words, whereas sublexical representations were used in version 3 of the same-different matching task to process the words. Finally, in version 2 of the same-different matching task individual variation was observed in the form of distinct sublexical and lexical biases. Implications for the processing of spoken words are discussed.     

Spectral analysis of word-initial alveolar and velar plosives produced by Iranian children with cleft lip and palate

Spectral moment analysis (SMA) was used to describe voiceless alveolar and velar stop-plosive production in Persian-speaking children with repaired cleft lip and palate (CLP). Participants included 11 children with bilateral CLP who were undergoing maxillary expansion and 20 children without any type of orofacial clefts. Four of the children with CLP also exhibited backed (palatal) placement for alveolar stops. All children produced consonant-vowel-consonant nonsense words that targeted the plosives /t/ and /k/. SMA revealed that children with CLP had significantly reduced first spectral moment of /t/ and /t/-/k/ difference. Children with CLP who produced palatal stops for alveolar targets also had lower but non-significant first spectral moments for /t/ as compared with children with CLP who did not produce palatal stops. The results are consistent with previously reported findings for English-speaking children with repaired CLP and further suggest that maxillary arch constriction may be a contributing factor for (a) reduced spectral distinction of alveolar targets and/or (b) palatal substitutions for alveolar targets.     

A longitudinal acoustic study of the effects of the radial forearm free flap reconstruction on sibilants produced by tongue cancer patients

Acoustic properties of 980 tokens of sibilants /s, z, ∫/ produced by 17 Canadian English-speaking female and male tongue cancer patients were studied. The patients had undergone tongue resection and tongue reconstruction with a radial forearm free flap (RFFF). The spectral moments (mean, skewness) and frication duration were analysed in connected speech samples produced before the tongue resection, and 1, 6 and 12 months after the surgery. The effects of radiation therapy (RT) and inclusion of the floor of the mouth (FOM) were also studied. Acoustic changes were observed only on alveolar sibilants /s, z/ such that speech was found to improve towards normal over the 1-year period. The reduction of acoustic distinction between /s, z/ and /∫/ was short term. A history of RT and involvement of the FOM had no differing effects on outcomes compared with non-RT or non-FOM. Variability between individuals was found, accentuating the speaker-specific abilities for adaptation, compensation and relearning after oral reconstruction.