| dc.description.abstract | The present study investigated first language (L1) and second language (L2) Chinese categorization of tones and segments and use of tones and segments in lexical access. Previous research has shown that English listeners rely more on pitch height than pitch direction when perceiving lexical tones; however, it remains unclear if this superior use of pitch height aids English-speaking learners of Chinese in identifying the tones of Chinese that differ in initial pitch height. The present study aimed to investigate this issue to determine whether this pitch height advantage aids English-speaking Chinese learners in identifying the tones of Chinese by looking at the time course of categorization of Chinese tones that differed in initial pitch as well as segments. A norming study was first conducted to investigate the duration of acoustic input needed to hear tone and segment (rime) distinctions. In a gated AX discrimination task, native Chinese listeners and naïve English listeners heard increasingly large fragments of tonal pairs and segmental pairs that varied in the expected disambiguation point. The results of this norming study were used to select tonal and segmental stimulus pairs were controlled (as best as is possible) for the disambiguation timing in the next two experiments. Experiment 1 investigated the time course of categorization of tones and segments using a forced-choice gating task designed to tap into listeners’ identification of fragment categories taken from syllables that differ only in tones or only in segments. Native Chinese listeners and L1-English L2-Chinese listeners heard a single fragment of a Chinese word and identified either the tone or the rime of the heard fragment from two presented options. The results showed that the segmental contrasts had higher accuracy than tonal contrasts for both groups. The L2-Chinese listeners performed comparably to the native listeners on both tonal and segmental contrasts, and L2 Chinese listeners showed no advantage over native listeners. The second goal of this study was to investigate the time course of the use of tones and segments in lexical access. Previous work has shown that native Chinese listeners use tones and segments simultaneously in lexical access. Previous work on how second language learners of Chinese use tones in lexical access compared to segments showed that tones and segments are used at the same time; however, work in the segmental domain suggest that this should not be the case, and learners should struggle to use the new tones in online lexical access. As such, this work aimed to reinvestigate the timing of use of tones and segments in second language Chinese, as well as to compare learners’ use of tones and segments to native listeners with a highly time-sensitive measure: visual-world eye-tracking. Experiment 2 investigated the time course of use of tones and segments in online spoken word recognition for L1 and L2 groups. The same segmental and tonal pairs used in Experiment 1 were used in a visual-world eye-tracking experiment. Native Chinese listeners and L1-English L2-Chinese listeners saw two pairs of words displayed as corresponding images: one tonal pair and one segmental pair. Eye movements were recorded as participants heard a single target word in isolation and clicked on the corresponding picture. The eye movement data revealed that native Chinese listeners use tones and segments to begin constraining the lexical search at approximately the same time, and tonal information constrained the search more rapidly than did segments. The L2-Chinese learners showed segmental use comparable to that of native listeners; however, their tonal use was delayed by approximately 100 ms. In terms of speed, learners also showed more rapid use of tones in constraining the lexical search, although tones and segments were used to constrain the lexical search more slowly than they did for native listeners. These results are discussed in relation to recent L1 studies on lexical access of tones and segments and computational modeling of suprasegmental information. The results of this research is in line with previous work that showed tones and segments are used to constrain lexical access simultaneously; however, the current work does not support the conclusion that tones and segments are used in the same way, with tones constraining the lexical search faster than segments. It is suggested that the cause of this tone speed advantage is the number of competitors removed from competition when the processor is certain of a tone as opposed to certain of a segment or even rime. The present results also speak to the literature on the use of segmental and suprasegmental information in a second language and suggest that the timing of use of different cues to lexical identity is dependent on if that cue is used in the L1, since segments were processed at the same time as native speakers while tones were delayed. Speed of use seems to be independent of whether or not it is used in the L1, with both tones and segments being processed slower overall compared to native listeners. | |
