Susan G. Guion

An investigation of current models of second language speech perception: the case of Japanese adults' perception of English consonants.

This study reports the results of two experiments with native speakers of Japanese. In experiment 1, near-monolingual Japanese listeners participated in a cross-language mapping experiment in which they identified English and Japanese consonants in terms of a Japanese category, then rated the identifications for goodness-of-fit to that Japanese category. Experiment 2 used the same set of stimuli in a categorial discrimination test. Three groups of Japanese speakers varying in English-language experience, and one group of native English speakers participated. Contrast pairs composed of two English consonants, two Japanese consonants, and one English and one Japanese consonant were tested. The results indicated that the perceived phonetic distance of second language (L2) consonants from the closest first language (L1) consonant predicted the discrimination of L2 sounds. In addition, this study investigated the role of experience in learning sounds in a second language. Some of the consonant contrasts tested showed evidence of learning (i.e., significantly higher scores for the experienced than the relatively inexperienced Japanese groups). The perceived phonetic distance of L1 and L2 sounds was found to predict learning effects in discrimination of L1 and L2 sounds in some cases. The results are discussed in terms of models of cross-language speech perception and L2 phonetic learning.

Perceived phonetic dissimilarity and L2 speech learning: the case of Japanese /r/ and English /l/ and /r/

Abstract Previous research has demonstrated that English /r/ is perceptually more dissimilar from Japanese /r/ than English /l/ is for native Japanese (NJ) speakers. It has been proposed by the Speech Learning Model that the more distant an L2 sound (phonetic segment) is from the closest L1 speech sound, the more learnable the L2 sound will be (in: W. Strange (Ed.), Speech Perception and Linguistic Experience: Issues in Cross-language Research, York Press, Timonium, MD, 1995, p. 233). This hypothesis was evaluated in this study by investigating whether NJ speakers will have more success acquiring English /r/ than /l/. A longitudinal study examined the perception (Experiment 1) and production (Experiment 2) of English /l/, /r/, and/w/ by NJ adults and children who were living in the US at the time of testing. The results suggested that there was greater improvement for English /r/ than English /l/ among the NJ children. The NJ childrens discrimination of /l/-/r/ and /r/-/w/ was significantly better at the second testing (T2) than 1 year earlier (T1). The NJ children also showed greater improvement from T1 to T2 in producing /r/ than /l/. The results are taken as support for a hypothesis of the Speech Learning Model (in: W. Strange (Ed.), Speech Perception and Linguistic Experience: Issues in Cross-language Research, York Press, Timonium, MD, 1995, p. 233) that degree of perceived phonetic dissimilarity influences L2 learners’ success in acquiring L2 phonetic segments.

The vowel systems of Quichua-Spanish bilinguals. Age of acquisition effects on the mutual influence of the first and second languages.

This study investigates vowel productions of 20 Quichua-Spanish bilinguals, differing in age of Spanish acquisition, and 5 monolingual Spanish speakers. While the vowel systems of simultaneous, early, and some mid bilinguals all showed significant plasticity, there were important differences in the kind, as well as the extent, of this adaptability. Simultaneous bilinguals dffered from early bilinguals in that they were able to partition the vowel space in a more fine-grained way to accommodate the vowels of their two languages. Early and some mid bilinguals acquired Spanish vowels, whereas late bilinguals did not. It was also found that acquiring Spanish vowels could affect the production of native Quichua vowels. The Quichua vowels were produced higher by bilinguals who had acquired Spanish vowels than those who had not. It is proposed that this vowel reorganization serves to enhance the perceptual distinctiveness between the vowels of the combined first- and second-language system.

The effect of L1 use on pronunciation in Quichua–Spanish bilinguals

Abstract This study investigated the interaction of the L1 and L2 systems in bilinguals by assessing the effect of L1 use on L1 and L2 production accuracy. A novel design feature of this study is that it examined bilinguals who used their L1 on a regular basis in a bilingual setting: Otavalo, Ecuador. Thirty native Quichua speakers who were matched for age of Spanish acquisition were recruited to form three groups differing in self-reported L1 use. The three groups repeated aurally presented sentences from their L1 and L2. Monolingual listeners from each language rated the blocked, randomly presented sentences for degree of foreign accent. For the Spanish sentences, the group with the highest L1 use had stronger Quichua accents than the group with the lowest L1 use. On the other hand, L1 use had no effect on the ratings of the Quichua sentences. Results from an analysis of Korean–English bilinguals are also reported. These results replicate the finding that L1 use affects L2, but not L1 production. These findings indicate that the interaction of the L1 and L2 systems affects the success of L2 acquisition, providing evidence that factors other than neurological maturation influence L2 acquisition.

Age of Learning Effects on the Duration of Sentences Produced in a Second Language.

Research has shown that L2 utterances diverge increasingly from target language phonetic norms as the age of L2 learning increases. Other research has suggested that L2 speakers produce longer utterances than native speakers. The aim of this study was to determine whether L2 utterance durations increase as age of learning increases. Fluently produced English sentences spoken by 240 native speakers of both Italian and Korean (selected on the basis of age of arrival [AOA]) were examined. For both L1 groups, the duration of English sentences was positively correlated with AOA. The AOA effect was found to be significant even when confounding variables were partialed out. These results are taken as preliminary support for the proposal that the more established the L1 is at the time of first exposure to the L2, the more it will interfere with L2 production, thus requiring greater processing resources to suppress it.

Clear speech production of Korean stops: Changing phonetic targets and enhancement strategiesa)

The proposal that phonological contrast is enhanced through greater approximation of phonetic targets was investigated by comparing clear speech to conversational and citation-form speech produced by Korean speakers. The stop system of Korean is undergoing a sound change in which younger speakers produce the aspirated-lenis stop contrast differently from previous generations. Older speakers differentiate this contrast primarily with the acoustic correlate of voice onset time (VOT) and secondarily with F0. Younger speakers are merging VOT values for this contrast. As a result, the primary acoustic correlate is now F0 for younger speakers. These production differences likely indicate that younger speakers have developed different phonetic targets for stop production. These different phonetic targets were predicted to result in different enhancement patterns in clear speech: Younger speakers were predicted to enhance F0 differences, whereas older speakers were predicted to enhance VOT differences in clear speech. Results indicated that the older group solely used VOT to enhance the contrast in clear speech, whereas the younger group primarily used F0 but also demonstrated small VOT enhancement. These results indicate that clear speech enhancement strategies reflect phonetic targets. Older and younger speakers have different F0 and VOT targets and these different targets conditioned different enhancement strategies.

Phonological systems in bilinguals : Age of learning effects on the stop consonant systems of Korean-English bilinguals

Interaction of Korean and English stop systems in Korean-English bilinguals as a function of age of acquisition (AOA) of English was investigated. It was hypothesized that early bilinguals (mean AOA=3.8 years) would more likely be native-like in production of English and Korean stops and maintain greater independence between Korean and English stop systems than late bilinguals (mean AOA=21.4 years). Production of Korean and English stops was analyzed in terms of three acoustic-phonetic properties: voice-onset time, amplitude difference between the first two harmonics, and fundamental frequency. Late bilinguals were different from English monolinguals for English voiceless and voiced stops in all three properties. As for Korean stops, late bilinguals were different from Korean monolinguals for fortis stops in voice-onset time. Early bilinguals were not different from the monolinguals of either language. Considering the independence of the two stop systems, late bilinguals seem to have merged English voiceless and Korean aspirated stops and produced English voiced stops with similarities to both Korean fortis and lenis stops, whereas early bilinguals produced five distinct stop types. Thus, the early bilinguals seem to have two independent stop systems, whereas the late bilinguals likely have a merged Korean-English system.

Acoustic analysis of the production of unstressed english vowels by early and late Korean and Japanese bilinguals

The production of unstressed vowels in English by early and late Korean- and Japanese-English bilinguals was investigated. All groups were nativelike in having a lower fundamental frequency for unstressed as opposed to stressed vowels. Both Korean groups made less of an intensity difference between unstressed and stressed vowels than the native speakers (NSs) of English as well as less of a difference in duration between the two types of vowel than the NSs. The Japanese speakers, whose native language has a phonemic length distinction, produced more nativelike durational patterns. Finally, the vowel quality (first and second formant frequencies) of unstressed vowels was different from the NS groups for the late bilinguals, for whom unstressed vowels were widely dispersed in the vowel space according to their orthographic representations, and from the early Korean bilinguals, who substituted the Korean high central vowel. The results are discussed in terms of the effect of the phonological status of first language phonetic features and age of acquisition. This work was supported by the Korea Research Foundation (KRF-2003-042-A00048) and partially supported by the National Institutes of Health (DC05132). A draft of this research was presented at the English phonology workshop division held for the 50th anniversary of the English Language and Literature Association of Korea (June 2004). The authors would like to thank four anonymous SSLA reviewers and Jonathan Loftin for their helpful comments on the manuscript.

Acoustic covariants of length contrast in Japanese stops

This study explores acoustic correlates to the singleton vs. geminate stop length contrast in Japanese. The proposal examined is that multiple acoustic features covary with the stop length distinction and that these features are available in the signal as potential secondary cues. The results support the proposal, revealing the presence of several acoustic features covarying with the singleton vs. geminate contrast in both durational and non-durational domains. Specifically, the preceding vowel is longer, the following vowel is shorter, there are greater fundamental frequency and intensity changes from the preceding to the following vowel, and there is evidence of more creakiness in voice quality for geminate than singleton consonants. It is also demonstrated that the vowel durations, as well as fundamental frequency and intensity changes have fairly strong categorization power.

Perceptual discrimination of Thai tones by naive and experienced learners of Thai

This study investigated the ability to discriminate the middle and low tone contrasts in Thai by two groups of native English (NE) speakers and a control group of native Thai (NT) speakers. The first group was comprised of NE speakers who had no prior experience with Thai, whereas subjects in the second group were experienced learners of Thai (EE). The variables under investigation were experience with Thai, discrimination of open versus closed syllables, and the interstimulus interval (ISI) of the presentation (500 vs 1500 ms). The results obtained indicated that the NT group obtained higher discrimination scores than the NE or EE groups, the EE group obtained higher discrimination scores than the NE group, all three groups of subjects found open syllables to be more difficult to discriminate than closed syllables, and subjects in the EE group obtained higher discrimination scores for open syllables in the shorter than the longer ISI condition.