Purpose: Vocal roughness is often present in many voice disorders but the assessment of roughness mainly depends on the subjective auditory-perceptual evaluation and lacks acoustic correlates. This study aimed to apply the concept of roughness in general sound quality perception to vocal roughness assessment and to characterize the relationship…

Purpose: The speech motor system uses feedforward and feedback control mechanisms that are both reliant on prediction errors. Here, we developed a state-space model to estimate the error sensitivity of the control systems. We examined (a) whether the model accounts for the error sensitivity of the control systems and (b) whether the two systems…

This article reports on the second language (L2) perception of contrasts among British English monophthongs. This study has two aims: 1) to explore the discriminability of contrasts in L2 British English monophthongs; and 2) to test the perceptual assimilation model-L2 (PAM-L2) towards the ability to discriminate British English contrasts. The…

A great deal of the research on cross-linguistic phonetic influence demonstrates that a speaker's knowledge of their first language (L1) significantly affects their ability to perceive and produce sounds in any other language. While current studies show that cross-linguistic transfer occurs at the L3 level, some research suggests that properties…

This dissertation investigates the hypothesis that the more vowel-like a consonant is, the more difficult it is for listeners to classify it as geminate or singleton. A perceptual account of this observation holds that more vowel-like consonants lack clear markers to signal the beginning and ending of the consonant, so listeners don't perceive the…

Adult second language (L2) learners often experience difficulty producing and perceiving non-native phonological contrasts. Even highly proficient bilinguals, who have been exposed to an L2 for long periods of time, struggle with difficult contrasts, such as /r/-/l/ for Japanese learners of English. To account for the relative ease or difficulty…

In an attempt to understand what acoustic/auditory feature sets motivated transcribers towards certain labeling decisions, I built machine learning models that were capable of discriminating between canonical and non-canonical vowels excised from the Buckeye Corpus. Specifically, I wanted to model when the dictionary form and the transcribed-form…

Speech production is inextricably linked to speech perception, yet they are usually investigated in isolation. In this study, we employed a verbal-repetition task to identify the neural substrates of speech processing with two ends active simultaneously using functional MRI. Subjects verbally repeated auditory stimuli containing an ambiguous vowel…

This paper tests the predictions of the vocabulary-tuning model of second language (L2) rephonologization in the domain of L2 segmental production. This model proposes a facilitating effect of adults' L2 vocabulary expansion on L2 perception and production and suggests that early improvements in L2 segmental production may be positively associated…

This study investigated English speakers' perception of Mandarin sounds, aiming to answer three major questions. First, does the perceived similarity between Mandarin and English sounds affect learners' acquisition of Mandarin sounds? Second, do the groups with different amounts of Mandarin experience differ in their perception of…

Recent literature has sought to understand the presence of epenthetic vowels after the productions of postvocalic word-final consonants by second language (L2) learners whose first languages (L1s) restrict the presence of obstruents in coda position. Previous models include those in which epenthesis is seen as a strategy to mitigate the effects of…

A variety of studies have demonstrated that organizing stimuli into categories can affect the way the stimuli are perceived. We explore the influence of categories on perception through one such phenomenon, the perceptual magnet effect, in which discriminability between vowels is reduced near prototypical vowel sounds. We present a Bayesian model…

This dissertation examines the relationship between the structural, phonemic properties of vowel inventories and their acoustic phonetic realization, with particular focus on the adequacy of Dispersion Theory, which maintains that inventories are structured so as to maximize perceptual contrast between their component vowels. In order to assess…

Time is essential to speech. The duration of speech segments plays a critical role in the perceptual identification of these segments, and therefore in that of spoken words. Here, using a French word identification task, we show that vowels are perceived as shorter when attention is divided between two tasks, as compared to a single task control…

This study investigated the effects of first language prosodic transfer on the perception and production of English lexical stress and the relation between stress perception and production by second language learners. To test the effect of Thai tonal distribution rules and stress patterns on native Thai speakers' perception and production of…