Purpose: Vocal fold asymmetry creates irregular entrainments and modulations in voice, which may lead to rough perceptual quality. The presence of asymmetry can also cause mid-phonation bifurcations where a small change in the phonatory system causes a drastic change in vibration pattern, resulting in transitions in and out of rough voice. This…

Purpose: The purpose of this investigation was to examine the impact of instruction order on the speech production response when adopting higher effort speaking styles, specifically loud and clear speech. Method: Speech intensity, lip aperture range, and speech rate data were collected from 24 talkers who repeated the utterance "Buy Bobby a…

Purpose: Previous studies have investigated the effects of the inability to produce hand gestures on speakers' prosodic features of speech; however, the potential effects of encouraging speakers to gesture have received less attention, especially in naturalistic settings. This study aims at investigating the effects of encouraging the production…

Purpose: This study investigated the efficacy of ultrasound biofeedback compared to a traditional acoustic input-only method in the second-language (L2) production training of English tense-lax vowel contrasts (/i-[near-close near-front unrounded vowel]/ and /e-[open-mid front unrounded vowel]/). The relationship between the degrees of production…

Purpose: This study aimed to (a) relate temporal patterning of articulation to functional speech outcomes in neurologically healthy and impaired speakers, (b) identify changes in temporal patterning of articulation in neurologically impaired speakers, and (c) evaluate how these changes can be modulated by speaking rate manipulation. Method:…

Purpose: Talkers typically use a slow speaking rate when producing clear speech, a speaking style that has been widely shown to improve intelligibility over conversational speech in difficult communication environments. With training, however, talkers can learn to produce a form of clear speech at normal speaking rates that provides young…

Arabic emphasis refers to the production of consonants resulting from a primary constriction in the dental or alveolar region and a secondary constriction in the back of the vocal tract, recognized as 'Emphatic.' These have contrastive consonants produced in the dental or alveolar region, recognized as 'Plain.' The existing research on emphasis in…

This dissertation investigates language-specific acoustic and aerodynamic phenomena in language contact situations. Whereas most work on second language and bilingual phonology has focused on individual consonants and vowels, this project examines patterns of coarticulation in the two languages of Spanish-English and French-English bilingual…

Purpose: This study examines the effect of age on language use with an automated analysis of digitized speech obtained from semistructured, narrative speech samples. Method: We examined the Cookie Theft picture descriptions produced by 37 older and 76 young healthy participants. Using modern natural language processing and automatic speech…

Children are known to be fast learners due to their neural plasticity. Learning a non-native language (L2) requires the mastering of new production patterns. In classroom settings, learners are not only exposed to the acoustic input, but also to the unfamiliar grapheme-phoneme correspondences of the L2 orthography. We tested how 9-10-year-old…

This dissertation examines the relative effects of phonetic salience and phonological prominence on speech sound processing. Three test cases, respectively, investigate the processing of consonants versus vowels by speakers of German, Hebrew, and Amharic; the processing of aspirated versus unaspirated stops by speaker of Spanish and Thai; and the…

Purpose: We investigated whether rhythm discrimination is mainly driven by the native language of the listener or by the fundamental design of the human auditory system and universal cognitive mechanisms shared by all people irrespective of rhythmic patterns in their native language. Method: In multiple experiments, we asked participants to listen…

Onomatopoeia are frequently identified amongst infants' earliest words (Menn & Vihman, 2011), yet few authors have considered why this might be, and even fewer have explored this phenomenon empirically. Here we analyze mothers' production of onomatopoeia in infant-directed speech (IDS) to provide an input-based perspective on these forms.…

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: 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…