The Effects of Spoken Input on Learning the Spoken Forms of Second Language Words: Studies of Frequency of Exposure, Acoustic Variability, and Mode of Input
Abstract
This dissertation investigates the effects of three input factors—frequency of exposure, acoustic variability, mode of input— on learning productive knowledge of spoken forms of second language (L2) words. This thesis takes an integrated article format and is organized into (a) introduction (Chapter 1), (b) three main studies (Chapters 2, 3, & 4), and (c) conclusion (Chapter 5). The three studies involved Japanese university students learning 40 unfamiliar English words through encountering their spoken forms (and written forms in Study 3) while viewing pictures that conveyed their meanings. A picture-naming test was administered before, immediately after, and approximately one week after the treatment and the elicited speech samples were assessed for pronunciation and form-meaning connection. Study 1 (Chapter 2) investigated the effects of repetition. Seventy-five participants were randomly assigned to one of three conditions (1, 3, and 6 encounters), and their performance was assessed for pronunciation (accentedness, comprehensibility, processing time) and form-meaning connection (spoken form recall). Results showed that the number of exposures positively affected measures of form-meaning connection and pronunciation. Measurable learning gains occurred for comprehensibility after three encounters, while six encounters were necessary for foreign accent to be significantly reduced. Study 2 (Chapter 3) investigated acoustic variability and frequency of exposure. Eighty participants were randomly assigned to one of four conditions (3 encounters, 6 encounters 3 encounters with talker variability, and 6 encounters with talker variability). Spoken form recall and word stress accuracy were assessed. Results suggested that frequency of exposure promoted form-meaning mapping to a greater extent than talker variability, whereas talker variability had a stronger influence on word stress accuracy than frequency effects. Study 3 (Chapter 4) investigated input modality. Seventy-five participants were randomly assigned to one of three conditions (reading-while-listening, reading-only, listening-only). The elicited speech was assessed for spoken form recall, accentedness, and comprehensibility. Results showed that the reading-while-listening group outperformed the listening-only group in form recall. The reading-while-listening and listening-only groups sounded more nativelike and comprehensible compared to the reading-only group. This dissertation concludes with implications for researching and teaching L2 vocabulary as well as suggestions for future studies.