This dissertation investigates how the abstract representation of vowels affects spoken word recognition in Brazilian Portuguese and American English by examining two issues in theoretical phonology and speech processing: underspecification theory, and underlying representation when there is alternation. Three experiments were conducted in…

Purpose: Here, we examine the possibility that memory consolidation during a period of postpractice rest or nocturnal sleep can bolster speech motor learning in the absence of additional practice or effort. Method: Using web-administered experiments, 74 typical, American English talkers trained in a nonnative vowel contrast then had a 12-hr delay…

Purpose: Place and manner of articulation in American English-learning children's salient consonant-vowel-consonant-vowel (C[subscript 1]VC[subscript 2]V) target words (e.g., "baby," "bunny," and "cookie") were compared with their actual productions of these words. We hypothesized that target words with repeated place…

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…

This study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers' spontaneous speech addressed to their 11- to 24-month-old infants (infant-directed speech, IDS) and an adult experimenter (adult-directed speech, ADS). The data were collected between 2016 and 2018 in Aarhus, Denmark. Prosodic properties of Danish…

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…

There is a long-standing debate in the literature about the benefits that acoustic components of Infant Directed Speech (IDS) might have for infants' language acquisition. One of the highly contested features is vowel space expansion, which refers to the enlargement of the acoustic space between the corner vowels /i, u, a/ in IDS compared to Adult…

Purpose: This study aims at investigating the phonological development of the six guttural consonants of Jordanian Arabic, /[chi]/, /[voiced uvular fricative]/, /[voiceless pharyngeal fricative]/, /[voiced pharyngeal fricative]/, /[glottal stop]/, and /h/. Method: An articulation test is designed to involve two tasks: picture naming and…

Background: Previous research has found that high-frequency energy of speech signals decreased while wearing face masks. However, no study has examined the specific spectral characteristics of fricative consonants and vowels and the perception of clarity of speech in mask wearing. Aims: To investigate acoustic-phonetic characteristics of fricative…

Purpose: We examined the effect of bite block insertion (BBI) on lingual movements and formant frequencies in corner vowel and diphthong production in a sentence context. Method: Twenty young adults produced the corner vowels (/u/, /[open back unrounded vowel]/, [ae]/, /i/) and the diphthong /[open back unrounded vowel][near-close near-front…

While voicing contrasts in word-onset position are acquired relatively early, much less is known about how and when they are acquired in word-coda position, where accurate production of these contrasts is also critical for distinguishing words (e.g., dog vs. dock). This study examined how the acoustic cues to coda voicing contrasts are realized in…

Purpose: The purpose of the current study was to characterize clear speech production for speakers with and without Parkinson disease (PD) using several measures of working vowel space computed from frequently sampled formant trajectories. Method: The 1st 2 formant frequencies were tracked for a reading passage that was produced using habitual and…

Purpose: Delayed auditory feedback (DAF) interferes with speech output. DAF causes distorted and disfluent productions and errors in the serial order of produced sounds. Although DAF has been studied extensively, the specific patterns of elicited speech errors are somewhat obscured by relatively small speech samples, differences across studies,…

Infants born after fetal growth restriction (FGR)--an obstetric condition defined as the failure to achieve the genetic growth potential--are prone to neurodevelopmental delays, with language being one of the major affected areas. Yet, while verbal comprehension and expressive language impairments have been observed in FGR infants, children and…

This paper addresses how input variability in the adult phonological system is mastered in the output of young children in Akan, a Kwa language spoken in Ghana, involving variability between labio-palatalized consonants and front rounded vowels. The high-frequency variant involves a complex consonant which is expected to be mastered late, while…