Silvain Gerber

Vocal Change Patterns During a Teaching Day: Inter- and Intra-Subject Variability

OBJECTIVES To describe the mean voice changes of 22 female teachers during a typical workday, examine the inter- and intra-subject variability, and establish a typology of different voice patterns during the workday. METHODS For each participant, fundamental frequency (F0), harmonics-to-noise ratio (HNR), jitter, and shimmer were measured on sustained vowels at the beginning and at the end of the workday, at three different times during the school year. RESULTS The group mean pattern showed significant increases in F0 and HNR during the workday and significant decreases in jitter and shimmer. However, considerable inter- and intra-subject variability was observed. Based on the variation in the acoustic parameters during the workday, three different voice patterns were identified. The first is characterized by a greater F0 increase during the day, interpreted as a common, appropriate adaptation to vocal load. The second is characterized by a greater increase in HNR during the day and greater decreases in jitter and shimmer, interpreted as hyperfunctional voice production. The third is characterized by greater decreases in F0 and HNR and greater increases in jitter and shimmer, suggesting acute inflammation or muscle fatigue following the workday. CONCLUSIONS The observed variety of vocal patterns during the workday emphasizes the need to study this phenomenon individually and target different types of behaviors to develop tailored prevention and treatment methods.

Vowel Reduction in Coratino (South Italy): Phonological and Phonetic Perspectives

Vowel reduction may involve phonetic reduction processes, with nonreached targets, and/or phonological processes in which a vowel target is changed for another target, possibly schwa. Coratino, a dialect of southern Italy, displays complex vowel reduction processes assumed to be phonological. We analyzed a corpus representative of vowel reduction in Coratino, based on a set of a hundred pairs of words contrasting a stressed and an unstressed version of a given vowel in a given consonant environment, produced by 10 speakers. We report vowelformants together with consonant-to-vowel formant trajectories and durations, and show that these data are rather in agreement with a change in vowel target from /i e ɛ·ɔ u/ to schwa when the vowel is a non-word-initial unstressed utterance, unless the vowel shares a place-of-articulation feature with the preceding or following consonant. Interestingly, it also appears that there are 2 targets for phonological reduction, differing in F1 values. A “higher schwa” - which could be considered as /ɨ/ - corresponds to reduction for high vowels /i u/ while a “lower schwa” - which could be considered as /ə/ - corresponds to reduction for midhigh

Transfer of Learning: What Does It Tell Us About Speech Production Units?

Purpose Words, syllables, and phonemes have each been regarded as basic encoding units of speech production in various psycholinguistic models. The present article investigates the role of each unit in the interface with speech articulation, using a paradigm from motor control research. Method Seventy-six native speakers of French were trained to change their production of /be/ in response to an auditory feedback perturbation (auditory-motor learning). We then assessed the magnitude of learning transfer from /be/ to the syllables in 2 pseudowords (/bepe/ and /pebe/) and 1 real word (/bebe/) as well as the aftereffect on the same utterance (/be/) with a between-subjects design. This made it possible to contrast the amplitude of transfer at the levels of the utterance, the syllable, and the phoneme, depending on the position in the word. Linear mixed models allowed us to study the amplitude as well as the dynamics of the transfer and the aftereffect over trials. Results Transfer from the training utterance /be/ was observed for all vowels of the test utterances but was larger to the syllable /be/ than to the syllable /pe/ at word-initial position and larger to the 1st syllable than to the 2nd syllable in the utterance. Conclusions Our study suggests that words, syllables, and phonemes may all contribute to the definition of speech motor commands. In addition, the observation of a serial order effect raises new questions related to the connection between psycholinguistic models and speech motor control approaches.

Does the Visual Channel Improve the Perception of Consonants Produced by Speakers of French with Down Syndrome

Purpose This work evaluates whether seeing the speakers face could improve the speech intelligibility of adults with Down syndrome (DS). This is not straightforward because DS induces a number of anatomical and motor anomalies affecting the orofacial zone. Method A speech-in-noise perception test was used to evaluate the intelligibility of 16 consonants (Cs) produced in a vowel-consonant-vowel context (Vo = /a/) by 4 speakers with DS and 4 control speakers. Forty-eight naïve participants were asked to identify the stimuli in 3 modalities: auditory (A), visual (V), and auditory-visual (AV). The probability of correct responses was analyzed, as well as AV gain, confusions, and transmitted information as a function of modality and phonetic features. Results The probability of correct response follows the trend AV > A > V, with smaller values for the DS than the control speakers in A and AV but not in V. This trend depended on the C: the V information particularly improved the transmission of place of articulation and to a lesser extent of manner, whereas voicing remained specifically altered in DS. Conclusions The results suggest that the V information is intact in the speech of people with DS and improves the perception of some phonetic features in Cs in a similar way as for control speakers. This result has implications for further studies, rehabilitation protocols, and specific training of caregivers. Supplemental Material https://doi.org/10.23641/asha.6002267.

Investigating how children produce rotation and pointing movements when they learn to write letters

How do children learn to write letters? During writing acquisition, some letters may be more difficult to produce than others because certain movement sequences require more precise motor control (e.g., the rotation that produces curved lines like in letter O or the pointing movement to trace the horizontal bar of a T). Children of ages 6-10 (N = 108) wrote sequences of upper-case letters on a digitizer. They varied in the number of pointing and rotation movements. The data revealed that these movements required compensatory strategies in specific kinematic variables. For pointing movements there was a duration decrease that was compensated by an increase in in-air movement time. Rotation movements were produced with low maximal velocity but high minimal velocity. At all ages there was a global tendency to keep stability in the tempo of writing: pointing movements exhibited a duration trade-off whereas rotation movements required a trade-off on maximal and minimal velocity. The acquisition of letter writing took place between ages 6 and 7. At age 8 the children shifted focus to improving movement control. Writing automation was achieved around age 10 when the children controlled movement duration and fluency. This led to a significant increase in writing speed.

The elaboration of motor programs for the automation of letter production

We investigated how children learn to write letters. Letter writing evolves from stroke-by-stroke to whole-letter programming. Children of ages 6 to 9 (N=98) wrote letters of varying complexity on a digitizer. At ages 6 and 7 movement duration, dysfluency and trajectory increased with stroke number. This indicates that the motor program they activated mainly coded information on stroke production. Stroke number affected the older childrens production much less, suggesting that they programmed stroke chunks or the whole letter. The fact that movement duration and dysfluency decreased from ages 6 to 8, and remained stable at ages 8 and 9 suggests that automation of letter writing begins at age 8. Automation seems to require the elaboration of stroke chunks and/or letter-sized motor programs.