Refining and extending measures for fricative spectra, with special attention to the high-frequency rangea).

Fricatives have noise sources that are filtered by the vocal tract and that typically possess energy over a much broader range of frequencies than observed for vowels and sonorant consonants. This paper introduces and refines fricative measurements that were designed to reflect underlying articulatory and aerodynamic conditions These show differences in the pattern of high-frequency energy for sibilants vs non-sibilants, voiced vs voiceless fricatives, and non-sibilants differing in place of articulation. The results confirm the utility of a spectral peak measure (FM) and low-mid frequency amplitude difference (AmpD) for sibilants. Using a higher-frequency range for defining FM for female voices for alveolars is justified; a still higher range was considered and rejected. High-frequency maximum amplitude (Fh) and amplitude difference between low- and higher-frequency regions (AmpRange) capture /f-θ/ differences in English and the dynamic amplitude range over the entire spectrum. For this dataset, with spectral information up to 15 kHz, a new measure, HighLevelD, was more effective than previously used LevelD and Slope in showing changes over time within the frication. Finally, isolated words and connected speech differ. This work contributes improved measures of fricative spectra and demonstrates the necessity of including high-frequency energy in those measures.

A Review of Voice Disorders in School-Aged Children.

OBJECTIVES: The purpose of this study was to review literature concerning voice disorders in school-aged children. STUDY DESIGN: Integrative review. MATERIALS AND METHODS: A database search was conducted using PubMed, Web of Science, Academic Search Complete, CINAHL Complete, and Medline. All records included in this review were peer-reviewed journal articles that discussed voice disorders in children, conducted in the United States or Canada, written in English, and published between 2009 and 2019. RESULTS: Database searching identified 1,771 records and 551 duplicates were removed. A total of 1,220 records were screened and 949 records were excluded. Two hundred and seventy-one full-text records were screened and 12 records met inclusion criteria. Vocal fold nodules were the most commonly reported vocal fold pathology. The Consensus Auditory Perceptual Evaluation of Voice and endoscopy were the most commonly reported assessments. However, variations in practice patterns and access to voice services may exist. CONCLUSIONS: The findings highlight that school-aged children may face barriers in accessing voice services. As a result, continued analyses of the potential barriers that hinder identification and treatment of voice disorders in this population appear warranted.

Adult perception of stop consonant voicing in American-English-learning toddlers: Voice onset time and secondary cues.

Most studies of speech perception employ highly controlled stimuli. It is not always clear how such results extend to the processing of natural speech. In a series of experiments, we progressively explored the role of voice onset time (VOT) and potential secondary cues in adult labeling of stressed syllable-initial /b d p t/ produced by typically developing two-year-old learners of American English. Taken together, the results show the following: (a) Adult listeners show phoneme boundaries in labeling functions comparable to what have been established for adult speech. (b) Adult listeners can be sensitive to distributional properties of the stimulus set, even in a study that employs highly varied naturalistic productions from multiple speakers. (c) Secondary cues are available in the speech of two-year-olds, and these may influence listener judgments. Cues may differ across places of articulation and the VOT continuum. These results can lend insight into how clinicians judge child speech during assessment and also have implications for our understanding of the role of primary and secondary acoustic cues in adult perception of child speech.

Assessing vowel effects on voice quality, and voice quality effects on the respiratory system.

This study assesses (a) effects of vowel height and tense-lax status on the laryngeal closed quotient (CQ) and (b) whether respiratory volume changes vary with differences in CQ. German speakers produced words containing eight different vowels in normal and loud conditions. The only significant vowel effect was found for the /a:-a/ pair, with lower CQ in /a/ at normal intensity. There was an insignificant trend for lower CQ to be associated with more negative thoracic slopes. The CQ difference for the /a:-a/ contrast, which relies more on duration than other tense-lax pairs in German, requires further study.

Vowel Formants in Normal and Loud Speech.

Purpose This study evaluated how 1st and 2nd vowel formant frequencies (F1, F2) differ between normal and loud speech in multiple speaking tasks to assess claims that loudness leads to exaggerated vowel articulation. Method Eleven healthy German-speaking women produced normal and loud speech in 3 tasks that varied in the degree of spontaneity: reading sentences that contained isolated /i: a: u:/, responding to questions that included target words with controlled consonantal contexts but varying vowel qualities, and a recipe recall task. Loudness variation was elicited naturalistically by changing interlocutor distance. First and 2nd formant frequencies and average sound pressure level were obtained from the stressed vowels in the target words, and vowel space area was calculated from /i: a: u:/. Results Comparisons across many vowels indicated that high, tense vowels showed limited formant variation as a function of loudness. Analysis of /i: a: u:/ across speech tasks revealed vowel space reduction in the recipe retell task compared to the other 2. Loudness changes for F1 were consistent in direction but variable in extent, with few significant results for high tense vowels. Results for F2 were quite varied and frequently not significant. Speakers differed in how loudness and task affected formant values. Finally, correlations between sound pressure level and F1 were generally positive but varied in magnitude across vowels, with the high tense vowels showing very flat slopes. Discussion These data indicate that naturalistically elicited loud speech in typical speakers does not always lead to changes in vowel formant frequencies and call into question the notion that increasing loudness is necessarily an automatic method of expanding the vowel space. Supplemental Material https://doi.org/10.23641/asha.8061740.

Exploring the source of short-term variations in respiratory data.

This study explores short-term respiratory volume changes in German oral and nasal stops and discusses to what extent these changes may be explained by laryngeal-oral coordination. It is expected that respiratory volumes decrease more rapidly when the glottis and the vocal tract are open after the release of voiceless aspirated stops. Two experiments were performed using Inductance Plethysmography and acoustics, varying consonantal properties, loudness, and prosodic focus. Results show consistent differences in respiratory slopes between voiceless vs voiced and nasal stops, which are more extreme in a loud or focused position. Thus, respiratory changes can even occur at a local level.

Relations among subglottal pressure, breathing, and acoustic parameters of sentence-level prominence in German.

This study investigates whether acoustic correlates of prominence are related to actions of the respiratory system resulting in local changes of subglottal pressure (Psub). Simultaneous recordings were made of acoustics; intraoral pressure (Pio), as an estimate of Psub; and thoracic and abdominal volume changes. Ten German speakers read sentences containing a verb ending with /t/ followed by a noun starting with /t/. These /t#t/ sequences were typically realized as one /t:/ with a long intraoral pressure plateau. Sentence-level prominence was manipulated by shifting the position of contrastive focus within the sentences. The slope and peak values of Pio within the /t#t/ sequence were used to estimate differences in Psub across focus positions. Results show that prominence production is related to changes in the slope and maximum value of the pressure plateau. While pressure increases led to higher intensity, the increases did not relate to f0, hence, suggesting that local f0 changes primarily reflect laryngeal activity. Finally, strong individual differences were observed in the respiratory data. These findings confirm past reports of local Psub increases corresponding to sentence-level prominence. Speaker-specific activations of the respiratory system are interpreted in terms of motor equivalence, with laryngeal mechanisms also appearing to contribute to Psub changes.

Acoustic-Phonetic Versus Lexical Processing in Nonnative Listeners Differing in Their Dominant Language.

PURPOSE: Nonnative listeners have difficulty recognizing English words due to underdeveloped acoustic-phonetic and/or lexical skills. The present study used Boothroyd and Nittrouer's (1988)j factor to tease apart these two components of word recognition. METHOD: Participants included 15 native English and 29 native Russian listeners. Fourteen and 15 of the Russian listeners reported English (ED) and Russian (RD) to be their dominant language, respectively. Listeners were presented 119 consonant-vowel-consonant real and nonsense words in speech-spectrum noise at +6 dB SNR. Responses were scored for word and phoneme recognition, the logarithmic quotient of which yielded j. RESULTS: Word and phoneme recognition was comparable between native and ED listeners but poorer in RD listeners. Analysis of j indicated less effective use of lexical information in RD than in native and ED listeners. Lexical processing was strongly correlated with the length of residence in the United States. CONCLUSIONS: Language background is important for nonnative word recognition. Lexical skills can be regarded as nativelike in ED nonnative listeners. Compromised word recognition in ED listeners is unlikely a result of poor lexical processing. Performance should be interpreted with caution for listeners dominant in their first language, whose word recognition is affected by both lexical and acoustic-phonetic factors.

Relative Weighting of Semantic and Syntactic Cues in Native and Non-Native Listeners' Recognition of English Sentences.

OBJECTIVE: Non-native listeners do not recognize English sentences as effectively as native listeners, especially in noise. It is not entirely clear to what extent such group differences arise from differences in relative weight of semantic versus syntactic cues. This study quantified the use and weighting of these contextual cues via Boothroyd and Nittrouer's j and k factors. The j represents the probability of recognizing sentences with or without context, whereas the k represents the degree to which context improves recognition performance. DESIGN: Four groups of 13 normal-hearing young adult listeners participated. One group consisted of native English monolingual (EMN) listeners, whereas the other three consisted of non-native listeners contrasting in their language dominance and first language: English-dominant Russian-English, Russian-dominant Russian-English, and Spanish-dominant Spanish-English bilinguals. All listeners were presented three sets of four-word sentences: high-predictability sentences included both semantic and syntactic cues, low-predictability sentences included syntactic cues only, and zero-predictability sentences included neither semantic nor syntactic cues. Sentences were presented at 65 dB SPL binaurally in the presence of speech-spectrum noise at +3 dB SNR. Listeners orally repeated each sentence and recognition was calculated for individual words as well as the sentence as a whole. RESULTS: Comparable j values across groups for high-predictability, low-predictability, and zero-predictability sentences suggested that all listeners, native and non-native, utilized contextual cues to recognize English sentences. Analysis of the k factor indicated that non-native listeners took advantage of syntax as effectively as EMN listeners. However, only English-dominant bilinguals utilized semantics to the same extent as EMN listeners; semantics did not provide a significant benefit for the two non-English-dominant groups. When combined, semantics and syntax benefitted EMN listeners significantly more than all three non-native groups of listeners. CONCLUSIONS: Language background influenced the use and weighting of semantic and syntactic cues in a complex manner. A native language advantage existed in the effective use of both cues combined. A language-dominance effect was seen in the use of semantics. No first-language effect was present for the use of either or both cues. For all non-native listeners, syntax contributed significantly more to sentence recognition than semantics, possibly due to the fact that semantics develops more gradually than syntax in second-language acquisition. The present study provides evidence that Boothroyd and Nittrouer's j and k factors can be successfully used to quantify the effectiveness of contextual cue use in clinically relevant, linguistically diverse populations.

Longitudinal observations of typical English voicing acquisition in a 2-year-old child: Stability of the contrast and considerations for clinical assessment.

Early assessment of phonetic and phonological development requires knowledge of typical versus atypical speech patterns, as well as the range of individual developmental trajectories. The nature of data reporting in previous literature on typical voicing acquisition left aspects of the developmental process unclear and limited clinical applicability. This work extends a previous four-month group study to present data for one child over 12 months. Words containing initial /b p d t/ were elicited from a monolingual English-speaking 2-year-old child biweekly for 25 sessions. Voice onset time (VOT) was measured for each stop. For each consonant and recording session, we measured range as well as accuracy, overshoot and discreteness calculated for means and individual tokens. The results underscore the value of token-by-token analyses. They further reveal that typical development may involve an extended period of fluctuating voicing patterns, suggesting that the voiced/voiceless contrast may take months or years to stabilise.

Toward improved spectral measures of /s/: results from adolescents.

PURPOSE: This article introduces theoretically driven acoustic measures of /s/ that reflect aerodynamic and articulatory conditions. The measures were evaluated by assessing whether they revealed expected changes over time and labiality effects, along with possible gender differences suggested by past work. METHOD: Productions of /s/ were extracted from various speaking tasks from typically speaking adolescents (6 boys, 6 girls). Measures were made of relative spectral energies in low- (550-3000 Hz), mid- (3000-7000 Hz), and high-frequency regions (7000-11025 Hz); the mid-frequency amplitude peak; and temporal changes in these parameters. Spectral moments were also obtained to permit comparison with existing work. RESULTS: Spectral balance measures in low-mid and mid-high frequency bands varied over the time course of /s/, capturing the development of sibilance at mid-fricative along with showing some effects of gender and labiality. The mid-frequency spectral peak was significantly higher in nonlabial contexts, and in girls. Temporal variation in the mid-frequency peak differentiated ±labial contexts while normalizing over gender. CONCLUSIONS: The measures showed expected patterns, supporting their validity. Comparison of these data with studies of adults suggests some developmental patterns that call for further study. The measures may also serve to differentiate some cases of typical and misarticulated /s/.

The effects of data reduction in determining the schedule of voicing acquisition in young children.

PURPOSE: In this study, multiple measures of voicing acquisition were used to evaluate the extent to which developmental patterns based on voice onset time (VOT) mean data differed from those based on token-by-token analyses in typically developing 2-year-olds. METHOD: Multiple repetitions of words containing initial /b p d t/ were elicited from 10 English-speaking children biweekly for 4 months. VOT was measured for each stop. For each child, consonant, and recording session, means and ranges were obtained, as were measures of accuracy, discreteness, and overshoot calculated for session means and for individual tokens. RESULTS: The token-by-token analyses suggested lower accuracy and more category overlap than the session means and revealed an overshoot phase for all children. They also showed examples of both abrupt and gradual changes that were not always evident in the means. Measures of range, accuracy, discreteness, and overshoot all continued to change after statistically significant VOT differences were observed. CONCLUSIONS: The findings suggest that some aspects of voicing development may not be evident in analyses that rely on VOT mean data and patterns of statistical significance. Token-by-token measures provide a more complete picture of stages of voicing development than those based solely on mean VOT values.

Effects of consonant manner and vowel height on intraoral pressure and articulatory contact at voicing offset and onset for voiceless obstruents.

In obstruent consonants, a major constriction in the upper vocal tract yields an increase in intraoral pressure (P(io)). Phonation requires that subglottal pressure (P(sub)) exceed P(io) by a threshold value, so as the transglottal pressure reaches the threshold, phonation will cease. This work investigates how P(io) levels at phonation offset and onset vary before and after different German voiceless obstruents (stop, fricative, affricates, clusters), and with following high vs low vowels. Articulatory contacts, measured using electropalatography, were recorded simultaneously with P(io) to clarify how supraglottal constrictions affect P(io). Effects of consonant type on phonation thresholds could be explained mainly in terms of the magnitude and timing of vocal-fold abduction. Phonation offset occurred at lower values of P(io) before fricative-initial sequences than stop-initial sequences, and onset occurred at higher levels of P(io) following the unaspirated stops of clusters compared to fricatives, affricates, and aspirated stops. The vowel effects were somewhat surprising: High vowels had an inhibitory effect at voicing offset (phonation ceasing at lower values of P(io)) in short-duration consonant sequences, but a facilitating effect on phonation onset that was consistent across consonantal contexts. The vowel influences appear to reflect a combination of vocal-fold characteristics and vocal-tract impedance.

A lumped mucosal wave model of the vocal folds revisited: recent extensions and oscillation hysteresis.

This paper examines an updated version of a lumped mucosal wave model of the vocal fold oscillation during phonation. Threshold values of the subglottal pressure and the mean (DC) glottal airflow for the oscillation onset are determined. Depending on the nonlinear characteristics of the model, an oscillation hysteresis phenomenon may occur, with different values for the oscillation onset and offset threshold. The threshold values depend on the oscillation frequency, but the occurrence of the hysteresis is independent of it. The results are tested against pressure data collected from a mechanical replica of the vocal folds, and oral airflow data collected from speakers producing intervocalic /h/. In the human speech data, observed differences between voice onset and offset may be attributed to variations in voice pitch, with a very small or inexistent hysteresis phenomenon.

Phonetic variability in residual speech sound disorders: Exploration of subtypes.

PURPOSE: To explore whether subgroups of children with residual speech sound disorders (R-SSDs) can be identified through multiple measures of token-to-token phonetic variability. METHOD: Children with R-SSDs were recorded during a rapid multisyllabic picture naming task and an oral diadochokinetic task. Transcription-based and acoustic measures of token-to-token variability were derived. Articulation accuracy and general indices of language skills were also measured. RESULTS: Low correlations were observed between transcription-based and acoustic measures of phonetic variability, and among the acoustic measures themselves. Children who were the most variable on one measure were not necessarily highly variable on other measures. Transcription-based measures of variability were associated with language skills. CONCLUSIONS: Measures of phonetic variability did not identify children in the sample as consistently high or low. Data do not support the notion that clear subgroups based on phonetic variability can be reliably identified in children with R-SSDs. The link between highly variable phonetic output (quantified by transcription-based measures) and lower language skills requires further exploration.

Simultaneous measures of electropalatography and intraoral pressure in selected voiceless lingual consonants and consonant sequences of German.

This work assessed relationships among intraoral pressure (IOP), electropalatographic (EPG) measures, and consonant sequence duration, in the following obstruents, clusters, and affricates of German: /t/, /sh/, /sht/, and /tsh/. The data showed significant correlations between IOP and percentage of articulatory contact (PC) for all speakers, whereas duration and place of articulation (measured by the EPG center of gravity) contributed less to IOP changes. Speakers differed in the strength of this relationship, possibly reflecting differences in vocal tract morphology or degree of laryngeal abduction. Single-point EPG and IOP measures in fricatives showed consistent correspondences across consonantal contexts, but the relationships for the stops were more complex and reflected positional effects. Temporal compression was observed for both members of the cluster, but only the fricative portion of the affricate. Conversely, coarticulation was observed for both the stop and fricative portion of the affricate, but only for the stop portion of the cluster, possibly reflecting biomechanical constraints. No clear differences were observed in coarticulatory resistance for stops and fricatives. These data contribute to a limited literature on articulatory-aerodynamic relationships in voiceless consonants and consonant sequences, and will provide a baseline for considering longer combinations of obstruents.

Speech production variability in fricatives of children and adults: results of functional data analysis.

This study investigates token-to-token variability in fricative production of 5 year olds, 10 year olds, and adults. Previous studies have reported higher intrasubject variability in children than adults, in speech as well as nonspeech tasks, but authors have disagreed on the causes and implications of this finding. The current work assessed the characteristics of age-related variability across articulators (larynx and tongue) as well as in temporal versus spatial domains. Oral airflow signals, which reflect changes in both laryngeal and supralaryngeal apertures, were obtained for multiple productions of /h s z/. The data were processed using functional data analysis, which provides a means of obtaining relatively independent indices of amplitude and temporal (phasing) variability. Consistent with past work, both temporal and amplitude variabilities were higher in children than adults, but the temporal indices were generally less adultlike than the amplitude indices for both groups of children. Quantitative and qualitative analyses showed considerable speaker- and consonant-specific patterns of variability. The data indicate that variability in /s/ may represent laryngeal as well as supralaryngeal control and further that a simple random noise factor, higher in children than in adults, is insufficient to explain developmental differences in speech production variability.

Stop-consonant voicing and intraoral pressure contours in women and children.

Previous authors have established that stop consonant voicing is more limited in young children than adults, and have ascribed this to immature vocal-tract pressure management. Physical development relevant to speech aerodynamics continues into adolescence, suggesting that consonant voicing development may also persist into the school-age years. This study explored the relationship between stop consonant voicing and intraoral pressure contours in women, 5 year olds, and 10 year olds. Productions of intervocalic /p b/ were recorded from eight speakers at each age. Measures were made of stop consonant voicing and delta, a measure designed to characterize the time course of intraoral pressure increase in stops, following Muller and Brown [Speech and Language: Advances in Basic Research and Practice, edited by N. Lass (Academic, Madison, 1980), Vol. 4, pp. 318-389]. Age effects for stop consonant voicing and delta were not statistically significant, but correlations between delta and stop voicing were less often significant and sometimes reversed in the children, providing some evidence of immature aerodynamic control. The current data, as well as those of Muller and Brown, also show that the delta measure may yield some paradoxical values, indicating that more work is needed on methods of assessing time-varying characteristics of intraoral pressure.

Laryngeal and aerodynamic adjustments for voicing versus devoicing of /h/: a within-speaker study.

The aim of this within-speaker case study was to explore how effectively a phonetically trained speaker could alter the likelihood of voicing around abduction, and what changes he made to do so. An American English-speaking male produced intervocalic /h/ in varying loudness and vowel contexts. When given no specific instructions about voicing (block 1), he produced almost entirely voiced /h/. He was then asked to devoice /h/ (block 2). Measures of voicing, baseline airflow, pulse amplitudes, fundamental frequency (F0), open quotient, and speed quotient were made from oral airflow signals. Subglottal pressure was estimated from intraoral pressures during /p/. In block 2, the speaker produced 70% devoiced /h/. He achieved this by making several changes associated with higher phonation threshold pressures: greater abduction degrees, lower subglottal pressures, greater longitudinal tension of the vocal folds, and altered laryngeal settings. Qualitative inspection of the DC flow contours along with correlational and principal components analyses indicated widespread changes in respiratory, laryngeal, and supralaryngeal settings, and differing interrelationships among variables. Our speaker showed tacit knowledge of the range of parameters affecting voicing. Differing relationships among variables across the two blocks support a view of phonation as a dynamic process, where speakers adjust multiple parameters, simultaneously.