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.…

Background: Individuals with intellectual disability (ID) often demonstrate speech impairments and reduced intelligibility. However, traditional treatment methods, which involve using repetitive verbal and non-verbal exercises, may not be fully suitable for this population. As adults with ID tend to lose interest and motivation facing the demands…

Purpose: The aim of the current study was to examine /l/ developmental patterns in young learners of Southern American English, especially in relation to the effect of word position and phonetic contexts. Method: Eighteen children with typically developing speech, aged between 2 and 5 years, produced monosyllabic single words containing singleton…

Purpose: Real-time magnetic resonance imaging (MRI) and accompanying analytical methods are shown to capture and quantify salient aspects of apraxic speech, substantiating and expanding upon evidence provided by clinical observation and acoustic and kinematic data. Analysis of apraxic speech errors within a dynamic systems framework is provided…

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 study was aimed at investigating what kind of lip positions are selected by Japanese adult participants for an unfamiliar Mandarin rounded vowel /y/ and if their lip positions are related to and/or differentiated from those for their native vowels. Method: Videotaping and post hoc tracking measurements for lip positions, namely…

This longitudinal study assessed three acoustic components of maternal infant-directed speech (IDS) -- pitch, affect, and vowel hyperarticulation -- in relation to infants' age and their expressive vocabulary size. These three individual components were measured in IDS addressed to infants at 7, 9, 11, 15, and 19 months (N = 18). All three…

This dissertation presents three studies that examined issues related to the production and the perception of pitch in a tone language. The first study examined linguistic contexts that may modulate consonant-induced pitch perturbations (CF0) in a tone language. Previous studies have produced mixed findings regarding the role of linguistic…

Background: Articulatory excursion and vocal intensity are reduced in many children with dysarthria due to cerebral palsy (CP), contributing to the children's intelligibility deficits and negatively affecting their social participation. However, the effects of speech-treatment strategies for improving intelligibility in this population are…

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…

Purpose: This study investigates the production of voiceless alveolar and postalveolar fricatives and affricates by bilingual and monolingual children with hearing loss who use cochlear implants (CIs) and their peers with normal hearing (NH). Method: Fifty-four children participated in our study, including 12 Spanish-English bilingual CI users (M…

Information from auditory feedback plays an important role in speech motor control. This has been shown in particular in experiments that make real-time changes to speakers' own productions, which are fed back to them while speaking (e.g. Houde and Jordan 1998). In response, speakers change their articulations so that their own altered feedback…

Research attempting to understand the intermediate stages of first-language acquisition and disordered speech has led to the discovery of covert contrast. A covert contrast is a statistically reliable difference between phonemes that is produced by a language learner, but in a way that cannot be heard readily by a listener of the target language.…

Purpose: The purpose of this study was to determine the effects of biofeedback on control of nasalization in individuals with typical speech. Method: Forty-eight individuals with typical speech attempted to increase and decrease vowel nasalization. During training, stimuli consisted of consonant-vowel-consonant (CVC) tokens with the center vowels…