Purpose: Speech production deficits and reduced intelligibility are frequently noted in individuals with Down syndrome (DS) and are attributed to a combination of several factors. This study reports acoustic data on vowel production in young adults with DS and relates these findings to perceptual analysis of speech intelligibility. Method:…

Purpose: Hypophonia (low speech intensity) is the most common speech symptom experienced by individuals with Parkinson's disease (IWPD). Previous research suggests that, in IWPD, there may be abnormal integration of sensory information for motor production of speech intensity. In the current study, intensity of auditory feedback was systematically…

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 aim of this study was to determine how the speech disorder profiles in Down syndrome (DS) relate to reduced intelligibility, atypical overall quality, and impairments in the subsystems of speech production (phonation, articulation, resonance, and prosody). Method: Auditory-perceptual ratings of intelligibility, overall quality, and…

Background: Developmental dysarthria is a motor speech impairment commonly characterized by varying levels of reduced speech intelligibility. The relationship between intelligibility deficits and acoustic vowel space among these individuals has long been noted in the literature, with evidence of vowel centralization (e.g., in English and…

Purpose: Poor nonword repetition accuracy is a hallmark of children with developmental language disorder (DLD). However, other diagnostic categories also show impaired nonword repetition performance relative to children with typical development (TD); therefore, this task is currently a sensitive but nonspecific index of DLD. In this study, we…

Purpose: Children with dysarthria secondary to cerebral palsy may experience reduced speech intelligibility and diminished communicative participation. However, minimal research has been conducted examining the outcomes of behavioral speech treatments in this population. This study examined the effect of Speech Intelligibility Treatment (SIT), a…

Purpose: Very preterm (VPT) children are at risk for speech and language problems throughout school age. However, little is known about early speech sound production in these children. This study aims to present a detailed description of early speech sound production and its trajectories in VPT children from 2 to 4 years of age. In addition, this…

Purpose: This study examined the acoustic properties of Taiwanese (Southern Min) lexical tones produced in esophageal speech (ES) and pneumatic artificial laryngeal speech (PAL), including onset fundamental frequency (F0), slope of F0 contour, duration, and amplitude (intensity) of the vowel portion of syllables carrying seven Taiwanese tones.…

Purpose: Most acoustic and articulatory studies on /l/ have focused on either duration, formant frequencies, or tongue shape during the constriction interval. Only a limited set of data exists for the transition characteristics of /l/ to and from surrounding vowels. The aim of this study was to examine second formant (F2) transition…

Purpose: The aims of this study were to assess the reliability and validity of the Computer Articulation Instrument (CAI), a speech production test battery assessing phonological and speech motor skills in 4 tasks: (1) picture naming, (2) nonword imitation, (3) word and nonword repetition, and (4) maximum repetition rate (MRR). Method: Normative…

Purpose: The authors investigated how different variants of clear speech affect segmental and suprasegmental acoustic measures of speech in speakers with Parkinson's disease and a healthy control group. Method: A total of 14 participants with Parkinson's disease and 14 control participants served as speakers. Each speaker produced 18 different…

The purpose of this article is to report results of an investigation into the production of a covert contrast by native speakers of Korean, Portuguese, and Spanish in the acquisition of the English distinction between the high front vowels /i/ and /?/. A covert contrast is a statistically reliable acoustic distinction made by a language learner…

The objective of this study was to investigate the perceptual relevance of acoustic differences in vowels produced by 6 children between the ages of 9-13 years old with unilateral cochlear implants. Formant frequencies were estimated for 12 repetitions of vowels /hid/, /hed/, /haed/, /hud/, /hUd/, and /hAd/ produced by the children. The estimated…

Despite the importance of speech naturalness to treatment outcomes, little research has been done on what constitutes speech naturalness and how to best maximize naturalness in relationship to other treatment goals like intelligibility. In addition, previous literature alludes to the relationship between prosodic aspects of speech and speech…