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…

Individual speakers' speech patterns differ from one another, despite presumably similar language input. What are the sources of this individual variability? In this dissertation, I explore sources of individual differences in pronunciation of coronal obstruents (/s/, /t[superscript h]/, /c[superscript h]/, /c/) at the ends of nouns in Korean.…

Purpose: Children with speech sound disorders (SSDs) often struggle with forming early representations for phonemes and words, which could impact their speech production as well as their lexical access. This difficulty may limit their ability to accurately identify nonexemplar productions of words, such as developmental misarticulations produced…

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…

I investigate the acquisition of affrication in Québec French (QF), where affricates are in complementary distribution with coronal stops, being realized before high front vowels and glides. Previous research on other languages shows that affricates are acquired before branching onsets, which supports the idea that complexity at the level of the…

Purpose: Phonologically complex targets (e.g., [pl-]) are understood to facilitate widespread gains following speech sound intervention, and yet, available research largely features word-"initial" clusters. The present study investigates intervention effects following treatment of complex clusters presented in word-"final"…

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…

The current study examined whether or not lexical access is influenced by detailed phonological features during the silent reading of Chinese sentences. We used two types of two-character target words (Mandarin sandhi-tone and base-tone). The first characters of the words in the sandhi-tone condition had a tonal alternation, but no tonal…

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…

Much research in child speech development suggests that young children coarticulate more than adults. There are multiple, not mutually-exclusive, explanations for this pattern. For example, children may coarticulate more because they are limited by immature motor control. Or they may coarticulate more if they initially represent phonological…

Purpose: This study investigated articulatory patterns for American English /[Voiced alveolar approximant]/ in children with and without a history of residual speech sound disorder (RSSD). It was hypothesized that children without RSSD would favor bunched tongue shapes, similar to American adults reported in previous literature. Based on clinical…

Across languages, certain syllables are systematically preferred to others (e.g., "plaf > ptaf"). Here, we examine whether these preferences arise from motor simulation. In the simulation account, ill-formed syllables (e.g., "ptaf") are disliked because their motor plans are harder to simulate. Four experiments compared…

Down syndrome is a genetic disorder which is represented by a variety of deficits in all linguistic domains including phonology. Previous research, mainly conducted in the English language, has documented phonological deficits in early childhood in Down syndrome. Given the paucity of research in the area of phonology in the Greek language, the aim…

This review describes a computational approach for modeling the development of speech motor control in infants. We address the development of two levels of control: articulation of individual speech sounds (defined here as phonemes, syllables, or words for which there is an optimized motor program) and production of sound sequences such as phrases…

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…