Reading Fluency in Children and Adolescents Who Stutter

Speech fluency is a major challenge for young persons who stutter. Reading aloud, in particular, puts high demands on fluency, not only regarding online text decoding and articulation, but also in terms of prosodic performance. A written text has to be segmented into a number of prosodic phrases with appropriate breaks. The present study examines to what extent reading fluency (decoding ability, articulation rate, and prosodic phrasing) may be altered in children (9–12 years) and adolescents (13–17 years) who stutter compared to matched control participants. Read speech of 52 children and adolescents who do and do not stutter was analyzed. Children and adolescents who stutter did not differ from their matched control groups regarding reading accuracy and articulation rate. However, children who stutter produced shorter pauses than their matched peers. Results on prosodic phrasing showed that children who stutter produced more major phrases than the control group and more intermediate phrases than adolescents who stutter. Participants who stutter also displayed a higher number of breath pauses. Generally, the number of disfluencies during reading was related to slower articulation rates and more prosodic boundaries. Furthermore, we found age-related changes in general measures of reading fluency (decoding ability and articulation rate), as well as the overall strength of prosodic boundaries and number of breath pauses. This study provides evidence for developmental stages in prosodic phrasing as well as for alterations in reading fluency in children who stutter.

Speech modifications in interactive speech: effects of age, sex and noise type

When attempting to maintain conversations in noisy communicative settings, talkers typically modify their speech to make themselves understood by the listener. In this study, we investigated the impact of background interference type and talker age on speech adaptations, vocal effort and communicative success. We measured speech acoustics (articulation rate, mid-frequency energy, fundamental frequency), vocal effort (correlation between mid-frequency energy and fundamental frequency) and task completion time in 114 participants aged 8–80 years carrying out an interactive problem-solving task in good and noisy listening conditions (quiet, non-speech noise, background speech). We found greater changes in fundamental frequency and mid-frequency energy in non-speech noise than in background speech and similar reductions in articulation rate in both. However, older participants (50+ years) increased vocal effort in both background interference types, whereas younger children (less than 13 years) increased vocal effort only in background speech. The presence of background interference did not lead to longer task completion times. These results suggest that when the background interference involves a higher cognitive load, as in the case of other speech of other talkers, children and older talkers need to exert more vocal effort to ensure successful communication. We discuss these findings within the communication effort framework. This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’.

Speech Development Between 30 and 119 Months in Typical Children II: Articulation Rate Growth Curves

Purpose We aimed to develop normative growth curves for articulation rate during sentence repetition for typically developing children. Our primary goal was the development of quantile/percentile growth curves so that typical variation in articulation rate with age could be estimated. We also estimated when children became adultlike in their articulation rate, and we examined the contributions of age and utterance length to articulation rate. Method This cross-sectional study involved collection of in-person speech samples from 570 typically developing children (297 girls; 273 boys) who passed speech, language, and hearing screening measures. Pauses greater than 150 ms in duration were removed from the samples, and articulation rate was measured in syllables per second (sps). Results Articulation rate reliably increased with age and utterance length. Rate in all key percentiles increased with age. The median rate (50th percentile) increased from 2.7 sps at 36 months to 3.3 sps at 96 months. The 5th percentile increased from 2.3 to 3.1 sps over the same age range. Using 3.2 sps as a benchmark for adultlike speech, we found the 25th, 50th, and 75th percentiles reached adultlike rates at 99, 75, and 53 months, respectively. Conclusions Articulation rate increases from early childhood into middle childhood, and it is generally adultlike by 10 years of age. Variability in articulation rate among typical children was substantial. Implications for prior research and for clinical usage are discussed.

Automated Analysis of Digitized Letter Fluency Data

The letter-guided naming fluency task is a measure of an individual’s executive function and working memory. This study employed a novel, automated, quantifiable, and reproducible method to investigate how language characteristics of words produced during a fluency task are related to fluency performance, inter-word response time (RT), and over task duration using digitized F-letter-guided fluency recordings produced by 76 young healthy participants. Our automated algorithm counted the number of correct responses from the transcripts of the F-letter fluency data, and individual words were rated for concreteness, ambiguity, frequency, familiarity, and age of acquisition (AoA). Using a forced aligner, the transcripts were automatically aligned with the corresponding audio recordings. We measured inter-word RT, word duration, and word start time from the forced alignments. Articulation rate was also computed. Phonetic and semantic distances between two consecutive F-letter words were measured. We found that total F-letter score was significantly correlated with the mean values of word frequency, familiarity, AoA, word duration, phonetic similarity, and articulation rate; total score was also correlated with an individual’s standard deviation of AoA, familiarity, and phonetic similarity. RT was negatively correlated with frequency and ambiguity of F-letter words and was positively correlated with AoA, number of phonemes, and phonetic and semantic distances. Lastly, the frequency, ambiguity, AoA, number of phonemes, and semantic distance of words produced significantly changed over time during the task. The method employed in this paper demonstrates the successful implementation of our automated language processing pipelines in a standardized neuropsychological task. This novel approach captures subtle and rich language characteristics during test performance that enhance informativeness and cannot be extracted manually without massive effort. This work will serve as the reference for letter-guided category fluency production similarly acquired in neurodegenerative patients.

MASSED TASK REPETITION IS A DOUBLE-EDGED SWORD FOR FLUENCY DEVELOPMENT

To examine the effects of task repetition with different schedules, English-as-a-foreign-language classroom learners performed the same oral narrative task six times under three different schedules. They narrated the same six-frame cartoon story (a) six times consecutively in one class (massed practice), (b) three times at the beginning and at the end of a class (short-spaced practice), and (c) three times as a part of two classes 1 week apart (long-spaced practice). The results yielded by an immediate posttest using a novel cartoon showed that massed practice reduced breakdown fluency (mid-clause and clause-final pauses) the most. However, the participants in the massed-practice group showed degraded speed (slower articulation rate) and repair fluency (more verbatim repetition). The effects of repetition schedule seem limited on a 1-week delayed posttest involving a novel cartoon. Yet, when participants narrated the same practiced cartoon 1 week later, massed practice also resulted in more verbatim repetition.

Intelligibility, Articulation Rate, Fluency, and Communicative Efficiency in Typically Developing Children

Purpose This article describes the developmental trajectories of four communication-related parameters (i.e., intelligibility, articulation rate, fluency, and communicative efficiency) in a cross-sectional study of typically developing children between 3 and 9 years. The four target parameters were related to auditory-perceptual parameters of speech function. Method One hundred forty-four typically developing children (ages 3;0–9;11 [years;months]; 72 girls and 72 boys) participated. Speech samples were collected using the materials of the Bogenhausen Dysarthria Scales for Childhood Dysarthria, a German assessment tool for childhood dysarthria, and analyzed following established auditory-perceptual criteria on relevant speech functions. To assess intelligibility, naïve listeners transcribed sentences repeated by the children. Articulation rate and fluency were measured by acoustic analyses; communicative efficiency was determined by multiplying the proportion of correctly transcribed syllables by speech rate. Results Intelligibility showed a steep developmental trajectory, with the majority of children obtaining a proportion of intelligible syllables close to 1.0 at the age of 5 years. Articulation rate demonstrated a flatter trajectory, with high variability still within the older children. Disfluencies, on the contrary, occurred only in the youngest children. By definition, communicative efficiency shared the characteristics of intelligibility and rate curves. A principal component analysis revealed, among other findings, strong connections between intelligibility and articulation, as well as between communicative efficiency, articulation, and rate measures. Conclusions While children speak intelligibly, in terms of the applied assessment, at a comparably young age, other communication-relevant parameters show a slower developmental progress. Knowledge on the typical development of communication-related parameters and on their complex relationships with functional speech variables is crucial for the clinical assessment of childhood dysarthria. Supplemental Material https://doi.org/10.23641/asha.14880285

Deficit or Difference? Effects of Altered Auditory Feedback on Speech Fluency and Kinematic Variability in Adults Who Stutter

Purpose The purpose of this study was to test whether adults who stutter (AWS) display a different range of sensitivity to delayed auditory feedback (DAF). Two experiments were conducted to assess the fluency of AWS under long-latency DAF and to test the effect of short-latency DAF on speech kinematic variability in AWS. Method In Experiment 1, 15 AWS performed a conversational speaking task under nonaltered auditory feedback and 250-ms DAF. The rates of stuttering-like disfluencies, other disfluencies, and speech errors and articulation rate were compared. In Experiment 2, 13 AWS and 15 adults who do not stutter (AWNS) read three utterances under four auditory feedback conditions: nonaltered auditory feedback, amplified auditory feedback, 25-ms DAF, and 50-ms DAF. Across-utterance kinematic variability (spatiotemporal index) and within-utterance variability (percent determinism and stability) were compared between groups. Results In Experiment 1, under 250-ms DAF, the rate of stuttering-like disfluencies and speech errors increased significantly, while articulation rate decreased significantly in AWS. In Experiment 2, AWS exhibited higher kinematic variability than AWNS across the feedback conditions. Under 25-ms DAF, the spatiotemporal index of AWS decreased significantly compared to the other feedback conditions. AWS showed lower overall percent determinism than AWNS, but their percent determinism increased under 50-ms DAF to approximate that of AWNS. Conclusions Auditory feedback manipulations can alter speech fluency and kinematic variability in AWS. Longer latency auditory feedback delays induce speech disruptions, while subtle auditory feedback manipulations potentially benefit speech motor control. Both AWS and AWNS are susceptible to auditory feedback during speech production, but AWS appear to exhibit a distinct continuum of sensitivity.

Speech development between 30 and 119 months in typical children II: Articulation rate growth curves

Purpose: We aimed to develop normative growth curves for articulation rate during sentence repetition for typically developing children. Our primary goal was the development of quantile/percentile growth curves, so that typical variation in articulation rate with age could be estimated. We also estimated when children became adultlike in their articulation rate and we examined the contributions of age and utterance length to articulation rate.Method: This cross-sectional study involved collection of in-person speech samples from 570 typically developing children (297 girls; 273 boys) who passed speech, language, and hearing screening measures. Pauses greater than 150 ms in duration were removed from the samples, and articulation rate was measured in syllables per second (sps).Results: Articulation rate reliably increased with age and utterance length. Rate in all key percentiles increased with age. The median rate (50th percentile) increased from 2.7 sps at 36 months to 3.3 sps at 96 months. The 5th percentile increased from 2.3 to 3.1 sps over the same age range. Using 3.2 sps as a benchmark for adultlike speech, we found the 25th, 50th, and 75th percentiles reached adultlike rates at 99, 75, and 53 months, respectively.Conclusions: Articulation rate increases from early childhood into middle childhood, and it is generally adultlike by 10 years of age. Variability in articulation rate among typical children was substantial. Implications for prior research and for clinical usage are discussed.

Investigating speaker individuality in the Swiss Standard German of four Alemannic dialect regions: Consonant quantity, vowel quality, and temporal variables

While German-speaking Switzerland manifests a considerable amount of dialectal diversity, until the present day the phonetic interrelation of Alemannic (ALM) dialects and spoken Swiss Standard German (SSG) has not been studied with an acoustic phonetic approach on the speaker level. In this study, out of a pool of 32 speakers (controlled for sex, age, and education level) from 4 dialectologically distinct ALM areas, 16 speakers with 2 dialects were analysed regarding SSG consonant duration (in words whose ALM equivalents may or may not have a geminate), 8 speakers from the city of Bern (BE) were analysed for vowel quality, and 32 speakers were analysed for temporal variables, i.e., articulation rate (AR) and vocalic-speech percentage (%V). Results reveal that there is much intradialectal inter- and intraspeaker variation in all three aspects scrutinised, but especially regarding vowel quality of BE SSG mid vowels and temporal variables. As for consonant quantity, while intradialectal interspeaker variation was observed, speakers showed a tendency towards normalised SSG consonant durations that resemble the normalised consonant durations in their ALM dialect. In general, these results suggest that a speaker’s dialect background is only one factor amongst many that influence the way in which Swiss Standard German is spoken.