Purpose: Auditory feedback is thought to contribute to the online control of speech production. Yet, the standard method of estimating auditory feedback control (i.e., reflexive responses to auditory-motor perturbations), although sound, requires specialized instrumentation, meticulous calibration, unnatural tasks, and specific acoustic…

Purpose: The spectral powers of the modulations of vocal fundamental frequency (f[subscript o]) less than 3 Hz (low-frequency power, LFP) and between 3 and 8 Hz (middle-frequency power, MFP) had been established to indicate the audiovocal feedback status and vocal efficiency of a speaker, and a resonant voice may enhance the auditory-vocal…

Purpose: Prior work suggests that voice onset time (VOT) may be impacted by laryngeal tension: VOT means decrease when individuals with typical voices increase their fundamental frequency (f[subscript o]) and VOT variability is increased in individuals with vocal hyperfunction, a voice disorder characterized by increased laryngeal tension. This…

Purpose: This study sought to identify the articulator-specific mechanisms that underlie reduced and enhanced acoustic vowel contrast in talkers with dysarthria due to Parkinson's disease (PD). Method: Seventeen talkers with mild-moderate dysarthria due to PD and 17 controls completed a sentence repetition task using typical, slow, loud, and clear…

Purpose: We compare teens' and adults' imitation of sentences with shortened and lengthened voice onset time (VOT), in order to test whether purported age-based advantages in phonetic acquisition may be due to differences in imitative ability. Method: Teens (M[subscript age] = 13, n = 39) and adults (n = 31) completed an explicit imitation and…

Purpose: The question of what type of utterance--a sustained vowel or continuous speech--is best for voice quality analysis has been extensively studied but with equivocal results. This study examines whether previously reported differences derive from the articulatory and prosodic factors occurring in continuous speech versus sustained phonation.…

Purpose: This study examined the relationship between the magnitude of neck-surface vibration (NSV[subscript Mag]; transduced with an accelerometer) and intraoral estimates of subglottal pressure (P'[subscript sg]) during variations in vocal effort at 3 intensity levels. Method: Twelve vocally healthy adults produced strings of /p?/ syllables in 3…

Purpose: The primary purpose of this study was to determine the strength of interspeaker and intraspeaker articulatory-to-acoustic relations of vowel contrast produced by talkers with dysarthria and controls. Methods: Six talkers with amyotrophic lateral sclerosis (ALS), six talkers with Parkinson's disease (PD), and 12 controls repeated a…

Purpose: This study investigated the acoustic characteristics of spontaneous speech by talkers aged 9-14 years and their ability to adapt these characteristics to maintain effective communication when intelligibility was artificially degraded for their interlocutor. Method: Recordings were made for 96 children (50 female participants, 46 male…

Typically, the point vowels [i,?,u] are acoustically more peripheral in infant-directed speech (IDS) compared to adult-directed speech (ADS). If caregivers seek to highlight lexically relevant contrasts in IDS, then two sounds that are contrastive should become more distinct, whereas two sounds that are surface realizations of the same underlying…

Purpose: The impact of clear speech, increased vocal intensity, and rate reduction on acoustic characteristics of vowels was compared in speakers with Parkinson's disease (PD), speakers with multiple sclerosis (MS), and healthy controls. Method: Speakers read sentences in habitual, clear, loud, and slow conditions. Variations in clarity,…

Research has shown that young infants use contrasting acoustic information to distinguish consonants. This has been used to argue that by 12 months, infants have homed in on their native language sound categories. However, this ability seems to be positionally constrained, with contrasts at the beginning of words (onsets) discriminated earlier.…

Purpose: This study investigated how different instructions for eliciting clear speech affected selected acoustic measures of speech. Method: Twelve speakers were audio-recorded reading 18 different sentences from the Assessment of Intelligibility of Dysarthric Speech (Yorkston & Beukelman, 1984). Sentences were produced in habitual, clear,…

Purpose: Adult human vocal tracts display considerable morphological variation across individuals, but the nature and extent of this variation has not been extensively studied for many vocal tract structures. There exists a need to analyze morphological variation and, even more basically, to develop a methodology for morphological analysis of the…

Talkers are known to compensate only partially for experimentally-induced changes to their auditory feedback. In a typical experiment, talkers might hear their F1 feedback shifted higher (so that /[epsilon]/ sounds like /[ash]/, for example), and compensate by lowering F1 in their subsequent speech by about a quarter of that distance. Here, we…