English and Thai Speakers ’ Perception of Mandarin Tones

Language learners’ language experience is predicted to display a significant effect on their accurate perception of foreign language sounds (Flege, 1995). At the superasegmental level, there is still a debate regarding whether tone language speakers are better able to perceive foreign lexical tones than non-tone language speakers (i.e Lee et al., 1996; Burnham & Brooker, 2002). The current study aimed to shed some light on this issue. Specifically, 24 adult Thai and 21 adult English speakers, who had no knowledge on Mandarin prior to participation in the study, were recruited. The participants’ accuracy in the perception of 4 Mandarin tones (T1, T2, T3, T4) was individually examined using an identification test. 288 stimuli of /ti/, /ta/, /tu/, /tʂhi/, /tʂha/, and /tʂhu/ produced in 4 Mandarin tones were prepared. The stimuli were embedded in a carrier sentence, and were produced by a female and a male native Mandarin speaker. According to the results, (1) none of the participants achieved 100% accuracy in any of the perception tests; (2) in the perception of Mandarin T1 and T4, the Thai speakers significantly outperformed the English speakers; (3) the Thai speakers and the English speakers displayed very similar degrees of difficulty in the perception of Mandarin T2 and T3; (4) the Thai participants’ most serious confusion was in the discrimination of T2-T3, whereas the English participants showed significant confusion in the identification of T1-T2 and T2-T3. The findings suggest that tone language speakers may benefit more from their L1 in the perception of foreign lexical tones than did the non-tone language speakers. However, the degree of the beneficial effect identified was limited.


Introduction
Language experience is frequently viewed as a significant factor that affects language learners' perception of non-native speech sounds (So & Best, 2010).Many previous studies have intensively investigated native language (L1) influences on language learners' perception of a non-native sounds at the segmental level (e.g.Best, 1995;Best & Tyler, 2007;Ying, 2014), whereas there is a paucity of empirical evidence available at the superasegmental level (i.e.stress pattern, quantity contrasts).The present study, therefore, investigated the influence of listeners' L1 on their perception of L2 lexical tones.Particularly, it examined whether tone language speakers are more likely to have an accurate perception of non-native lexical tones than non-tone language speakers.If this proved to be the case, the intention was also to establish to what extent tone language speakers could outperform the non-tone language speakers.Some reports on non-native tone perception have suggested that tone language speakers are benefited from their L1 in the perception of non-native lexical tones more than non-tone language speakers.For instance, Lee et al. (1996) reported that native Cantonese speakers perceived Mandarin tones better than native English speakers did.Similarly, in a perception training study, Wayland and Guion (2004) found that native Mandarin Chinese listeners had better discrimination of Thai tones than native English listeners in their pre-test and post-test results.Moreover, native English speakers were revealed to focus on pitch height when perceiving tones, whereas tone-language speakers (i.e., Cantonese and Mandarin speakers) were revealed to focus on both pitch height and pitch direction in the perception of lexical tones (Gandour, 1983(Gandour, , 1984)).In general, these findings may have suggested that listeners whose L1 is a tone language are better able to have accurate perception of non-native lexical tones than those whose L1 is a non-tone language.
Nonetheless, this point of view might be compromised if we take a further look at the study conducted by Lee et al. (1996), which reported that the Cantonese subjects had an extensive exposure to Mandarin, which may have

Results of Tonal Confusions
The above results indicated the participants' tone sensitivity.Given that language listeners' L1 phonology system may display influence on their perception of foreign tones (So & Best 2010;Wayland & Guion, 2004;Lee et al., 1996), it would be necessary to investigate the participants' confusions on each tone.However, their answers (correct and incorrect ones) with a confidence score of 0 were excluded, because these responses were given by 'totally guessing'.As show in Table 2 and Table 3 above, the Thai participants did not show serious confusion between T1 and the other 3 tones, as their confusions (incorrect responses) between T1 and T2, T1 and T3, T1 and T4 all counted around 6%.A similar phenomenon was found to occur between T4 and T1, T4 and T3.However, they displayed a comparatively much higher degree of confusion in the differentiation of T2-T3, as they incorrectly identified target T2 as T3 (incorrect response: 24.71%), and T3 as T2 (incorrect response: 29.03%).
For the English speakers, they incorrectly identified target T1 as T2 with a percentage of 21.45%, and target T2 as T1 with a percentage of 18.50%.Moreover, the English participants also incorrectly identified target T2 as T3 and target T3 as T2 with a percentage of 15.33% and 21.90% respectively.The rest of the incorrect responses were all below 10%.Generally, therefore, the English participants showed significant confusions in the identification between T1 and T2 as well as between T2 and T3.

Discussion
The present study examined whether tone language speakers could be better able to perceive foreign lexical tones than non-tone language speakers.The findings of the study provided somewhat complicated results.First of all, the overall results showed that the Thai participants outperformed the English participants in the perception of the 4 tones (see Figure 3 and Table 4).Therefore, it might be tempting to assume that tonal language speakers benefit more from their L1 experience in the perception of foreign lexical tones than do non-tonal language speakers.This finding is consistent with those presented by Lee et al. (1996) and Wayland and Guion (2004).However, the participant group showing better performance (Cantonese speakers) in Lee et al. (1996) had extensive exposure to Mandarin, while the Thai participants of the present study did not.In other words, compared to Lee et al. (1996), the Thai participants' perception performance in the present study may be better able to provide supporting evidence for the influence of L1 on the perception of foreign lexical tones.Regarding the Wayland and Guion's (2004) study, although the tonal language speakers (Chinese) outperformed the non-tone language speakers (English) in the perception of Thai tones both before and after being trained, they only tested the speakers' identification of 2 Thai tones (mid tone vs. low tone).
The second finding was that the Thai participants significantly outperformed the English participants in the identification of T1 and T4.Unexpectedly, n the perception of T2 and T3, the English participants' A' scores were only slightly lower than that of the Thai participants.Although the Thai participants' good performance in the perception of T1 and T4 can be explained by the similarities between Mandarin and Thai tones, their low accuracy in the identification of T2 and T3 can hardly be attributed to this factor.However, this latter result could be explained by the fact that Mandarin T2 and T3 show shorter duration than their counterparts in Thai tones (Kwanrean, 2001).Moreover, So and Best (2010) suggests that T2-T3, T1-T2, T1-T4 are more confusable in terms of identification than other pairs, because they share some similar phonetic features.
Another significant finding was that the two groups of participants showed different confusion patterns among the 4 Mandarin tones.Thai participants' most significant confusion levels occurred in the identification between T2 and T3.The English participants, however, displayed serious confusions in T1-T2 and T2-T3.As discussed above, due to phonetic similarities, the 2 pairs of tones (T1-T2, T2-T3) are generally suggested to be more difficult to identify than the other tone pairs (So & Best, 2010).Moreover, the Thai participants' confusion may be caused by the durational difference between T2, T3 and their counterparts in the Thai language.
In addition, none of the participants achieved 100% accuracy in the identification test.In other words, even if the Thai participants were benefited by their L1, the degree of the benefit was limited.One of the limitations of the present study was that it lacked phonetic analysis, thus no evidence showed whether the English and Thai participants relied on the same acoustic cues in the identification test.As reported by Gandour (1983Gandour ( , 1984)), English speakers identify lexical tones through the perception of pitch height, whereas Cantonese and Mandarin speakers rely on both pitch height and pitch direction.Therefore, it may be able to argue that in the present study, the acoustic cue(s) that the Thai participants rely on were different from those employed by the English participants.

Conclusion
The present study investigated the influence of L1 influence on the perception of foreign lexical tones.The Thai and English participants' perception of Mandarin tones was compared.The findings indicated the Thai participants' overall accuracy of perception was higher than the English speakers.The Thai participants' most serious confusion was in the identification between T2 and T3.The English participants, on the other hand, displayed significant difficulty in the identification of tone pairs T1-T2 and T2-T3.The findings suggested that L1 does affect language listeners' identification of foreign lexical tones.Specifically, tone language speakers might be better able to perceive foreign lexical tones than non-tone language speakers.The unexpected finding of the study, which may shed some light on the topic of lexical tone perception, was that the English and Thai speakers displayed similar accuracy in the perception of Mandarin T2 and T3.In other words, the beneficial effect of tone language as an L1 is limited for the listeners' perception of foreign Lexical tones.
One of the limitations of the present study is that it did not examine whether the Thai and English participants relied on the same acoustic cues in the perception of the 4 Mandarin tones.Moreover, only Thai and English speakers' perception of lexical tones was tested.It would be interesting to examine the perception performance of speakers of other languages in future studies.

Table 3 .
Thai participants' confusion matrices in the identification test