Doctor of Philosophy, The Ohio State University, 2015, Linguistics

Voiceless sibilant fricatives, such as the consonant sounds at the beginning of the English words sea and she, are articulated by forming a narrow constriction between the tongue and the palate, which directs a turbulent jet of air toward the incisors downstream. Thus, the production of these sounds involves the movement of a number of articulators, including the tongue, jaw, and lips; however, the principal method for analyzing the acoustics of sibilant fricatives has been to extract a single “steady state” interval from near its temporal midpoint, and estimate spectral properties of this interval. Consequently, temporal variation in the spectral properties of sibilant fricatives has not been systematically studied. This dissertation investigated the temporal variation of a single spectral property that denotes the most prominent psychoacoustic frequency, i.e. peak ERB-number. The dynamic aspects of peak ERB-number trajectories were analyzed with fifth-order polynomial time growth curve models. A series of analyses revealed a number of novel findings A comparison of English- and Japanese-speaking adults indicated that both language-internal sibilant contrasts are indicated by dynamic properties of peak ERB-number across the time course of the sibilants. A cross-linguistic comparison indicated that the peak ERB-number of a sibilant follows a language-specific trajectory. Next, the development of the sibilant contrast in native English- and Japanese- acquiring children was investigated in terms of peak ERB-number trajectory. The English-acquiring children contrasted the sibilants in terms of similar aspects of peak ERB-number trajectory as the English-speaking adults. Moreover, the extent to which the children differentiated the sibilants increased with age. The analysis of the Japanese-acquiring children was complicated by an apparent developmental regression in the five-year-olds. Effects of vowel context on peak ERB-number trajectory were examined i (open full item for complete abstract)

Committee: Mary Beckman (Advisor); Micha Elsner (Committee Member); Eric Fosler-Lussier (Committee Member); Eric Healy (Committee Member) Subjects: Linguistics

PhD, University of Cincinnati, 2012, Allied Health Sciences: Communication Sciences and Disorders

Purpose: Fricatives are a class of sounds that is considered difficult to produce, and are generally developed later than stops, nasals and glides in speech sound development. Current understanding of fricative development suggests that children who develop fricatives at an early age may have better expressive language skills than children who do not develop fricatives early. The purpose of this study was to investigate the changes in fricative production, overall consonant production, and vocabulary growth in a group of toddlers who participated in a short-term, intensive auditory-perceptual intervention program. Methods: The study sample consisted of eight typically developing 18-month-old toddlers with half (n=4) in the treatment group and half (n=4) on the control group. Each toddler in both groups was visited 3 days a week for a period of 3 weeks. During each visit, a 15-minute session with a book-reading activity with a specially designed book and a play activity using selected toys and a play-script was conducted. The treatment group toddlers participated in an auditory-perceptual intervention with the book and the script designed to provide stimulation for the sounds /s/ and /z/. The control group toddlers participated in similar activities, however with materials designed to avoid stimulation of /s/ and /z/ sounds. Children's performance was assessed with speech samples and the vocabulary scores obtained at pre-treatment, post-treatment, and when the child reached 20 months of age (follow-up). A speech sample was also collected from each child before every treatment session. The assessment data were statistically analyzed to look at the differences in speech sound production and vocabulary over time for both groups of toddlers. Results: The number of fricative /s/ and /z/ productions, number of fricatives, number of fricative types, percentage of fricative types and vocabulary raw scores significantly changed over time for toddlers of both groups combined (open full item for complete abstract)

Committee: Nancy Creaghead PhD (Committee Chair); Chung-Yiu Chiu PhD (Committee Member); Jean Neils PhD (Committee Member); Carolyn Sotto PhD (Committee Member) Subjects: Speech Therapy

Doctor of Philosophy, The Ohio State University, 2012, Linguistics

The perception of non-native speech sounds is heavily influenced by the acoustic cues that are relevant for differentiating members of a listener's native (L1) phonological contrasts. Many studies of both (naive) non-native and (not naive) second language (L2) speech perception implicitly assume continuity in a listener's habits of perceptual attention to acoustic cues both before and after L2 instruction begins. In this dissertation we argue that while the ability to attend to familiar acoustic cues may not change as a listener begins to learn an L2, whether and how the acoustic cues will be attended to is the result of an interaction between L1-influenced bottom-up habits of perceptual attention and top-down information about the L2. This top-down information about the L2 is totally unavailable to a non-native listener but cannot be avoided by an L2 learner, as it is typically introduced at the earliest stages of L2 instruction. In this dissertation we look specifically at the emergence of the Korean /sh/-/s*/ perceptual contrast in L1 Mandarin and Japanese learners of Korean. Our results show that while naive L1 Mandarin listeners (but not L1 Japanese listeners) are sensitive to differences in aspiration when perceiving Korean /sh/ and /s*/, L1 Mandarin learners of L2 Korean fail to demonstrate such sensitivity and perform as poorly as L1 Japanese listeners. Even after one year of intensive Korean instruction for four hours per day, L1 Mandarin listeners show very little improvement, if any at all. We reconcile these differences between non-native and L2 perception by appealing to top-down information present in the orthography, romanization, and loanword vocabulary of Korean that conflicts with L1-influenced habits of perceptual attention.

Committee: Mary E. Beckman PhD (Advisor); Cynthia Clopper PhD (Committee Member); Shari Speer PhD (Committee Member) Subjects: Linguistics

Master of Arts, The Ohio State University, 2010, Linguistics

The study addresses one of the important questions in the field of speech perception: whether listeners process speech categorically as discrete units or continuously attuning to variation within phonemes. Recent research has demonstrated that listeners were able to identify stimuli with sub-phonemic variation in stop voicing contrasts and use this information during lexical processing. The present study seeks further support for this view by building categorical and continuous models based on distribution of individual listeners' responses in a goodness rating task. Lexical items varying along seven-step continua in initial stop voicing or sibilant fricative place are tested and compared against the models. The results show that listeners' perception of sub-phonemic variation is more consistent with the continuous model of speech perception.

Committee: Mary Beckman PhD (Advisor); Shari Speer PhD (Committee Member) Subjects: Linguistics

Doctor of Philosophy, The Ohio State University, 2008, Linguistics

% The dissertation abstract can only be 350 words. This dissertation examines the development of voiceless sibilant fricatives in children speaking English, Japanese or Mandarin Chinese. Both English and Japanese have a two-way distinction in sibilant fricatives (alveolar /s/ vs.post-alveolar /S/ in English and dental/alveolar /s/ vs. alveolopalatal /c}/ in Japanese), and Mandarin Chinese has a three-way contrast among dental/alveolar /s/, alveolopalatal /c}/ and retroflex /S/. Children's fricative productions have been traditionally described using adult's impressionistic transcriptions, which yield inconsistent orders of acquisition both across children and across languages. This dissertation argues that transcription filters children's early productions through adults' language-specific phonological systems, and therefore obscures the actual developmental patterns in children's speech. The purpose of the current study is to tease apart children's own productions from adults' interpretations of them by applying acoustic analyses to both adults' and children's productions and by systematically evaluating adults' perception patterns in tasks that allow more continuous responses. This dissertation first starts by examining the acoustics of adult productions in all three languages to parameterize the acoustic space for sibilant fricatives. It then investigates the production patterns of children speaking either English or Japanese, which has a two-way contrast in voiceless sibilant fricatives. Twenty 2-to-3-year old speakers of each of the two languages were tested to look for covert contrast in children's speech. The results show that adults are not able to recognize fine-grained phonetic differences that children make, and a more objective description of children's productions using methods such as acoustic analysis is needed. A set of perception experiments was then performed to further examine how English-speaking adults and Japanese-speaking adults would differ i (open full item for complete abstract)

Committee: Mary E. Beckman PhD (Advisor); Susan Nittrouer PhD (Committee Member); Cynthia Clopper PhD (Committee Member) Subjects: Linguistics; Psychology; Speech Therapy