Speech is a complex, redundant and variable signal happening in a noisy and ever changing world. How do listeners navigate these complex auditory scenes and continuously and effortlessly understand most of the speakers around them? Studies show that listeners can quickly adapt to new situations, accents and even to distorted speech. Although prior…

Language learners need to map a continuous, multidimensional acoustic signal to discrete abstract speech categories. The complexity of this mapping poses a difficult learning problem, particularly for second language learners who struggle to acquire the speech sounds of a non-native language, and almost never reach native-like ability. A common…

Reading is an essential skill for daily life and academic success. According to the connectionist model of reading, word recognition involves orthographic, phonological, and semantic processing, as well as the interactions among them. Language skill such as phonological processing, develops earlier than reading acquisition, and thus likely serves…

All language use reflects the user's social identity in systematic ways. While humans can easily adapt to this sociolinguistic variation, automatic speech recognition (ASR) systems continue to struggle with it. This dissertation makes three main contributions. The first is to provide evidence that modern state-of-the-art commercial ASR systems…

The purpose of this research is to investigate the relationship between early intervention providers' backgrounds, and their perceptions of caregiver coaching and auditory skill development, to develop professional development programs. An explanatory sequential design was used with participants of varying backgrounds and experience. In the first…

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 studies the perception of tones in Thai, and aims to contribute to a formal characterization of speech perception more generally. Earlier work had argued that perception of tones involves retrieval of some abstract "autosegmental" representation provided by the phonology, while another line of work had argued for the…

This dissertation proposes a dynamical computational model of the timecourse of phonological parameter setting. In the model, phonological representations embrace phonetic detail, with phonetic parameters represented as activation fields that evolve over time and determine the specific parameter settings of a planned utterance. Existing models of…

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…

Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

This dissertation examines the possible influence of language learners' second language (L2) on their perception of phonological contrasts in their third language (L3). Previous studies on Third Language Acquisition (TLA) suggest various factors as possible sources of cross-linguistic influence in the acquisition of an L3. This dissertation…

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…

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…

Traditional pronunciation instruction and instruction in second language (L2) phonetics have been shown to improve learners' L2 accent in some, though certainly not all, cases. Learners in intermediate and advanced Spanish FL courses have shown modest improvement in the pronunciation of some L2 phones after receiving such instruction.…