UBC Theses and Dissertations
Articulatory characteristics of English /l/ in speech development Oh, Sunyoung
This dissertation investigates articulatory characteristics of English /I/ in child speech. The study is primarily based on experimental data collected using ultrasound imaging techniques from eight English children ages 3;11 to 5;9. Replicating previous articulatory studies of syllable-based allophones of /I/ in adult speech production, the articulatory components of III in child speech production are analyzed for the static information and relative timing between tongue movements. Secondarily, the acoustic analysis of this data and its perception judgments by adults are presented.' One of the major findings of this study is that children at these ages produce /I/ using different spatial and temporal coordination than adult speech production, although some children produce /I/ more similar to adult /I/ in terms of articulatory organization. Further, the findings are addressed in relation to speech motor development, and hypotheses are tested to see which motor developmental process(es) (differentiation, integration, refinement) can describe the acquisition of /I/. The ultrasound results of the tongue movements in children's /I/ indicate that all general motor developmental processes are active in these children, and the spatial and temporal coordination of the articulatory gestures of /I/ is rather simplified or modified, and needs to be further refined. I argue that the tendency toward late acquisition of /I/ is due directly to the articulatory complexity of its spatial and temporal characteristics. This work contributes much-needeid empirical data of the articulatory characteristics of /I/ to both language acquisition and speech sciences and constitutes a novel application of ultrasound imaging to child speech research. Organization of this dissertation is as follows. Subsequent to the overall introduction of the study in Chapter 1, Chapter 2 presents the empirical background and hypotheses for the study. It reviews speech and developmental studies in production and perception conducted by other researchers, and proposes empirical questions. Chapter 3 provides the methodology for the study. It introduces ultrasound techniques and experiment design and procedure. Chapter 4 presents the results of the spatial characteristics of the children's /I/ in terms of number of gestures, tongue shape, constriction location, and allophonic variation with respect to different syllable positions. Chapter 5 discusses the results of the temporal characteristics of the children's /I/ gestures. Inter-gestural timing of allophones of /I/ is examined to determine whether timing distinguishes positional allophones in these children's speech. Chapter 6 provides post-experiment perception judgments made by adults, and acoustic analysis of samples of tokens used in the current study. Finally, Chapter 7 summarizes the results and discusses the implications of the dissertation.
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