Purpose: Recent studies have shown that an acoustic measure, relative fundamental frequency (RFF), has potential for the assessment of excessive laryngeal tension and vocal effort associated with functional and neurological voice disorders. This study presents an analysis of the test-retest reliability of RFF in individuals with healthy voices and…

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: 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…

A prominent hypothesis holds that by speaking to infants in infant-directed speech (IDS) as opposed to adult-directed speech (ADS), parents help them learn phonetic categories. Specifically, two characteristics of IDS have been claimed to facilitate learning: "hyperarticulation," which makes the categories more "separable," and…

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…

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…

This article investigates the production of the emphatic consonants /?, ?, ?/ by typically developing Jordanian children. Sixty typically developing monolingual Ammani Arabic-speaking children (30 boys and 30 girls) with ages ranging from 2 to 7;11 years were recruited in a production experiment. In the experiment, they were asked to produce 18…

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,…

Purpose: The purpose of the study was to investigate vowel-specific intelligibility and acoustic patterns of individuals with different severities of dysarthria secondary to amyotrophic lateral sclerosis (ALS). Method: Twenty-three individuals with dysarthria secondary to ALS and 22 typically aging individuals participated as speakers.…

In speech perception tasks with ambiguous bottom-up information, lexical processes have been shown to influence listener responses, such as in phoneme categorization tasks (Ganong, 1980). Proponents of interactive theories of speech perception and spoken word recognition assert this influence is a top-down feedback mechanism that can affect…

Covert contrast is the statistically reliable distinction between target language phonemes produced in the process of language acquisition that is nevertheless not perceived by a native speaker of that language. This paper examines the acquisition of contrasts in four Najdi Arabic fricatives, /s/, /[voiceless palato-alveolar fricative]/,…

Purpose: The purpose of this study was to explore the relationship between feedback and feedforward control of articulation and voice by measuring reflexive and adaptive responses to first formant (F[subscript 1]) and fundamental frequency (f[subscript o]) perturbations. In addition, perception of F[subscript 1] and f[subscript o] perturbation was…

Purpose: The purpose of this article was to validate a novel acoustic analysis of oral diadochokinesis (DDK) in assessing bulbar motor involvement in amyotrophic lateral sclerosis (ALS). Method: An automated acoustic DDK analysis was developed, which filtered out the voice features and extracted the envelope of the acoustic waveform reflecting the…

Language has a rhythmic structure, but little is known about the mechanisms that underlie how it is planned. Traditional models of language production assume that metrical and segmental planning occur independently and in parallel (Roelofs & Meyer, 1998). We test this claim in three experiments. In Experiment 1, participants completed an…

There is no one-to-one mapping between speech acoustics and individual speech sounds; instead, the acoustic cues produced for individual speech sounds show wide variability both within and across talkers. Nonetheless, listeners perceive the speech of familiar and novel talkers with ease. It is theorized that listeners achieve this feat by…