The original Spectral Correlation Index (SCI[underscore o]) is a measure of amplitude envelope distortion that has been used in several studies to predict behavioral results. Because the original SCI[underscore o] did not account for the differential contribution of particular frequency bands to speech intelligibility (i.e., band importance) or…

Purpose: This study explored the role of auditory feedback in the regulation of oral-nasal balance in speakers of Brazilian Portuguese. Method: Twenty typical speakers of Brazilian Portuguese (10 male, 10 female) wore a Nasometer headset and headphones while continuously repeating stimuli with oral and nasal sounds. Oral-nasal balance was…

Research on native Arabic speakers' perception of non-native English phonemic contrasts has manifested various conclusions. Some studies have revealed that native Arabic speakers experience difficulty in the perception of non-native English phonemic contrasts, where others have concluded that they largely do not experience such difficulty. Due to…

Purpose: This study aimed to examine whether abstract knowledge of word-level linguistic prosody is independent of or integrated with phonetic knowledge. Method: Event-related potential (ERP) responses were measured from 18 adult listeners while they listened to native and nonnative word-level prosody in speech and in nonspeech. The prosodic…

To understand spoken language, listeners combine acoustic-phonetic input with expectations derived from context (Dahan & Magnuson, 2006). Eye-tracking studies on semantic context have demonstrated that the activation levels of competing lexical candidates depend on the relative strengths of the bottom-up input and top-down expectations (cf.…

Purpose: The intelligibility of an accent strongly depends on the specific talker-listener pairing. To explore the causes of this phenomenon, we investigated the relationship between acoustic-phonetic similarity and accent intelligibility across native (1st language) and nonnative (2nd language) talker-listener pairings. We also used online…

According to the Shallow Structure Hypothesis (SSH), second language (L2) speakers, unlike native speakers, build shallow syntactic representations during sentence processing. In order to test the SSH, this study investigated the processing of a syntactic movement in both native speakers of English and proficient late L2 speakers of English using…

This dissertation begins with the observation of a typological asymmetry within phonological patterns related to phonetic naturalness. Patterns that are rooted within existing tendencies of perception and/or production--in other words, patterns that are phonetically "natural"--are common in phonological typology and seen in a variety of…

Recent research has shown that speakers are sensitive to non-contrastive phonetic detail present in nonnative speech (e.g. Escudero et al. 2012; Wilson et al. 2014). Difficulties in interpreting and implementing unfamiliar phonetic variation can lead nonnative speakers to modify second language forms by vowel epenthesis and other changes. These…

This study explored the developmental trends and phonetic category formation in bilingual children and adults. Participants included 30 fluent Spanish-English bilingual children, aged 8-11, and bilingual adults, aged 18-40. All completed gating tasks that incorporated code-mixed Spanish-English stimuli. There were significant differences in…

Previous research has argued that fundamental frequency is a critical component of phonetic accommodation. We tested this hypothesis in an auditory naming task with two conditions. Participants in an Unfiltered Condition completed an auditory naming task with a single male model talker. A second group of participants was assigned to a Filtered…

Purpose: To understand the components of auditory learning in typically developing children by assessing generalization across stimuli, across modalities (i.e., hearing, vision), and to higher level language tasks. Method: Eighty-six 8- to 10-year-old typically developing children were quasi-randomly assigned to 4 groups. Three of the groups…

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…

Models of speech perception are in general agreement with respect to the major cortical regions involved, but lack precision with regard to localization and lateralization of processing units. To refine these models we conducted two Activation Likelihood Estimation (ALE) meta-analyses of the neuroimaging literature on sublexical speech perception.…

Adults tend to perceive speech sounds from their native language as members of distinct and stable categories; however, they fail to perceive differences between many non-native speech sounds without a great deal of training. The present study investigates the effects of categorization training on adults' ability to discriminate non-native…