Acoust. Sci. & Tech. 40, 4 (2019) #2019 The Acoustical Society of Japan

Listening training in Japanese pitch accent for native speakers of Japanese: Relationship with sound sensitivity Kanae Amino National Research Institute of Police Science, 6–3–1 Kashiwanoha, Kashiwa, 277–0882 Japan (Received 18 March 2019, Accepted for publication 4 April 2019) Keywords: Perception of speech , Native language, Sound sensitivity PACS number: 43.10.Sv, 43.71.k [doi:10.1250/ast.40.285]

1. Introduction order to test the pitch accent patterns used in the two major Japanese pitch accent utilises two levels of pitch height. , that is, Kinki and Tokyo dialects. These Each , or syllable in some dialects, is associated with sixteen words were selected based on the following criteria in either high or low pitch. In most dialects, the accent patterns order to maintain comparability: no loan words, no compound for each word are fixed; however, the number of patterns and words, and no words containing vowel-devoicing environ- which patterns are used differ across dialects. This is one of ments. The common accent patterns for these words were the reasons Japanese pitch accent is difficult to acquire for confirmed in accent dictionaries [12,13], and it was also second language learners. Various training tools are available confirmed that the patterns basically do not vary. As shown for learners of [e.g. 1, 2]. Meanwhile, however, in Table 2, all accent patterns used in Tokyo dialect were some studies also report difficulty with pitch accent percep- covered by the selected words; however, those used in Kinki tion among native speakers of Japanese [3–5]. The ability to dialect could not be covered since not all patterns are actually accurately perceive accent patterns varies among individuals used in the present words. Kinki dialect has eight patterns for [4] and for more familiar versus less familiar dialects [3]. trimoraic words, although only four of these patterns were Perception of various phonetic cues, including accent patterns, covered in this study. The words and a non-sense word were is crucial for practical phoneticians, that is, those who wield then recorded in carrier sentences, that is, / gaaRW/ ‘we the knowledge of phonetics in their profession, such as have ’or/ ga nai/ ‘we do not have ’, using speech synthesis language teachers, speech therapists and forensic speech software that can produce speech from two characters investigators. However, there have been no training methods differing in dialect using single-speaker speech materials. proposed so far regarding the perception of Japanese accent The stimuli for Kinki dialect were produced by using the patterns by native speakers of Japanese [5]. Kansai Japanese’ character, and those for Tokyo dialect were Many studies have pointed out that the perception of pitch produced using the Common Japanese’ character. Finally, the in language prosody is related to that of musical pitch; and author, who is a trained phonetician, confirmed that the accent people with musical experience have advantages in the patterns were correctly realised and that no stimuli used in the production and perception of foreign language prosody experiment sounded unnatural. [6–11]. If this also holds for prosody perception in the native Three tasks were conducted to test sound sensitivity: language, Japanese native speakers’ perception of Japanese discriminations of pitch (T5), loudness (T6) and sound timbre pitch accent patterns may be improved by musical training, (T7). The stimuli were created using Praat [14] and DAW which includes sound sensitivity training. software (Adobe, Audition, CS6). For T5, pure tones of This study investigates Japanese native speakers’ percep- 131 Hz and 214 Hz were used as the base tones; these are the tion of Japanese pitch accent from the following viewpoints: average fundamental frequencies of male and female Japanese 1) ability differences among individuals, 2) the relation people aged between their 20s and their 60s, respectively [15]. between pitch accent perception and sound sensitivity, and 3) The base tones were then modified between 5 Hz and +5 Hz whether sound sensitivity training improves native speakers’ in 0.5 Hz steps. For T6, the same base tones were used, pitch accent perception. amplified between 4 dB and +4 dB in 0.5 dB steps. Harmonic complex tones were created to test T7 with their 2. Methodology centre frequencies set between 125 Hz and 8,000 Hz in octave 2.1. Tasks and stimuli steps and amplified by 10 dB. The experimental tasks are summarised in Table 1. Four For the discrimination tasks, all possible stimulus combi- tasks were used to test pitch accent perception: two discrim- nations were used in T1, T2, T5, and T6, while stimulus ination tasks (T1 and T3) and two identification tasks (T2 combinations of two neighbouring centre frequencies were and T4). A trimoraic non-sense word, /nanana/, and sixteen used in T7. The inter-stimulus duration was 0.5 seconds. trimoraic Japanese words, shown in Table 2, were used in 2.2. Participants Participants were recruited at universities in the vicinity of Tokyo. Thirty-five paid volunteers (sixteen female and e-mail: [email protected]

285 Acoust. Sci. & Tech. 40, 4 (2019)

Table 1 Tasks of the experiment.

Test ID Task Target Multiple-choices T1 Pitch accent of non-words Discrimination Same/Different T2 Pitch accent of words Accent T3 Pitch accent of non-words HLL(L)/LHL(L)/ Identification LHH(L)/LHH(H)/ T4 Pitch accent of words HHH(H)/LLL(H) T5 Pitch of pure tones High/Same/Low Sound T6 Discrimination Loudness of pure tones Loud/Same/Soft sensitivity T7 Timbre of complex tones Same/Different

Table 2 Stimuli used in the accent tasks: H and L stand them spoke Japanese as their native language, but their for high and low pitch associated for each mora, dialects were not controlled. respectively. H or L in the parentheses is for the For the experiment, participants were divided into three following nominative particle. groups: A) trained (sound sensitivity tasks preceding accent Dialect Type Pattern Words tasks), B) trained (accent tasks preceding sound sensitivity > tasks), and C) no training (only the accent tasks). Information 1 HLL(L) /kinoko/, /nimotsW/ on the participants in each group is summarised in Table 3. > 2 LHL(L) /omotCa/, /amado/ 2.3. Procedures Tokyo Experiments were conducted in a sound-treated room at 3 LHH(L) /hanaCi/, /mojaCi/ the National Research Institute of Police Science. Participants 0 LHH(H) /okazW/, /minato/ went through a hearing test before the experiment, and it was H1 HLL(L) /kagami/, /wasabi/ confirmed that hearing level was below 25 dB using four- frequency average hearing loss (4FAHL). A psychoacoustic H0 HHH(H) /kamado/, /mijage/ Kinki experiment system, Shinji (Nihon Onkyo Engineering), was L2 LHL(L) /iime/, /hazWRe/ used for the experiments. The stimuli were presented through L0 LLL(H) /iRoRi/, /omake/ an audio interface (RME, Fireface UC) and a headphone (SONY, MDR-CD900ST), at a comfortable level. The participants practised before each task using stimuli different from those used in the experiments. They were nineteen male) participated in the experiments. They came to forced to choose an answer from the multiple choices shown the experiments at least twice and at most four times, over a in Table 1. For all tasks, the participants could listen to each one- or two-month interval (37.7 days on average). All of stimulus only once, and feedback was given after they

Table 3 Information on the participants.

Group A Group B Group C Number of participants (female:male) 12 (6:6) 12 (5:7) 11 (5:6) Average age at time of first participation 21.3 24.2 21.9 Number of participants who have musical experience 10 (8) 8 (3) 8 (6) (before the age of 6) Kinki 0 1 0 Tokyo 9 8 8 Accent of the native dialect1Þ Nikei 0 1 0 Mukei 3 2 3 Twice 3 2 8 Number of times participating Three times 0 3 3 Four times 9 7 0

1) Based on the place of origin where they lived before they were 12 years old. Classification of the accent was made according to Sugito [16] cited in Kibe [17].

286 K. AMINO: TRAINING IN PITCH ACCENT FOR NATIVE SPEAKERS

Table 4 Mean correct rates and standard deviations of Table 5 Correlation between the results of the accent the first experiment. and sound-sensitivity tasks (first experiment; all par- ticipants, but for T5 to T7, Groups A and B only). Task Group A Group B Group C Asterisks show that the coefficient is statistically T1 87.9 (6.3) 87.1 (9.1) 86.6 (6.9) significant ( p < 0:01). T2 80.5 (12.8) 73.7 (18.1) 76.1 (14.5) T1 T2 T3 T4 T5 T6 T7 T3 58.1 (22.0) 57.6 (20.8) 61.4 (22.3) T1 1.00 0.78 0.66 0.51 0.69 0.05 0.06 T4 63.5 (22.8) 65.9 (23.8) 62.9 (21.9) T2 1.00 0.80 0.71 0.64 0:13 0.16 T5 63.5 (10.8) 63.1 (14.3) — T3 1.00 0.86 0.66 0.05 0.15 T6 75.7 (7.8) 77.9 (4.8) — T4 1.00 0.57 0.11 0.01 T7 78.4 (8.6) 75.6 (8.2) — T5 1.00 0.23 0.29 T6 1.00 0.26 T7 1.00 100

80 music showed a significant benefit in T2, T3, and T4, although 60 it was limited to experience before the age of six (p < 0:05). No effect of musical experience was confirmed in sound 40 sensitivity tasks.

Correct rate (%) 20 Table 5 shows the correlation coefficients among tasks in all participants’ results from the first experiment. There were 0 significant positive correlations among the four accent tasks T1 T2 T3 T4 T5 T6 T7 and between the pitch discrimination task (T5) and the accent tasks. The tasks using non-words, T1 and T3, showed higher Fig. 1 Distributions of the scores for each task. correlation to T5 than the corresponding tasks using real words, T2 and T4, respectively. This may be because non- words tasks do not involve language processing, and hence answered. Each stimulus was repeated twice, and the are more similar to the physical perception of pitch height presentation order of the stimuli was random. in T5. 3.2. Effects of the training 3. Results and discussion Between-group differences were examined using the data 3.1. Results of the first experiment from the second to the fourth experiments; however, no Average correct rates for T1 to T4 in the three groups and significant differences were found. This means that not only those for T5 to T7 in Groups A and B from the first the order of the tasks but even whether or not sound sensitivity experiment are shown in Table 4. Between-group differences training is conducted does not affect accent task performance. were not significant for any tasks. Results of one-way All previous studies [6–11] reporting musical training’s ANOVAs on the correct rates for all participants showed that positive influence on language prosody perception were about performance difference among the tasks was significant both the prosody of ‘foreign’ languages. The present results for the accent tasks (Fð3; 136Þ¼18:6, p < 0:001) and the suggest that the effect of musical training in Japanese native sound sensitivity tasks (Fð2; 69Þ¼16:9, p < 0:001). Tukey’s listeners’ perception of Japanese pitch accent may be limited. post-hoc test revealed that the participants performed signifi- The training effect itself was examined for all partic- cantly better in discrimination tasks (T1 and T3) than in ipants’ scores irrespective of the groups. The comparisons identification tasks (T2 and T4) (p < 0:05), and that the score between the scores of the first and second, second and third, was significantly better in loudness and timbre discrimination and third and fourth experiments revealed that performance (T6 and T7) than in pitch discrimination (T5) (p < 0:01). It improved significantly at each step. The changes in scores has long been known that discrimination tasks are easier are shown in Fig. 2. Some of the participants experienced than identification tasks [e.g. 18]. Poor performance in T5 faltering growth or even a decline; however, most participants compared to T6 and T7 may be due to difference in degree of improved their scores eventually. Conducting the accent tasks difficulty of the tasks. improved the scores, even though the interval between the Distributions among all participants’ scores for each task experiments was one or two months. are shown in Fig. 1. Here large variation among individuals are observed in the ability to identify the accent patterns. As 4. Conclusions pointed out in previous studies [3–5], some people are not This study investigated Japanese native speakers’ percep- good at identifying the accent patterns of their native tion of Japanese pitch accent and its relation to sound language. Whereas there was no significant effects of native sensitivity. The results showed that the ability to perceive dialects or social attributes (age, gender), the experience of accent patterns differs greatly among individuals, and some

287 Acoust. Sci. & Tech. 40, 4 (2019)

T1 T2 T3 T4 100 100 100 100 80 80 80 80 60 60 60 60 40 40 40 40 20 20 20 20 0 0 0 0 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th T5 T6 T7 100 100 100 80 80 80 60 60 60 40 40 40 20 20 20 0 0 0 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th

Fig. 2 Changes in the results for all participants for T1 to T7. Improvements are shown by solid lines, and declines are shown by dotted lines. people are not good at identifying the accent patterns of their Experience in Second Language Speech Learning, O. S. Bohn native dialect. Discrimination and identification of Japanese and M. J. Munro, Eds. (John Benjamins, Amsterdam, 2007), accent patterns correlated positively with discrimination of Chap. 13, pp. 221–237. pitch height. The effect of the sound sensitivity training on the [7] C. Y. Lee and T. H. Hung, ‘‘Identification of Mandarin tones improvement of the ability to perceive the pitch accent was by English-speaking musicians and nonmusicians,’’ J. Acoust. Soc. Am., 124, 3235–3248 (2008). not significant; however, conducting the pitch accent tasks [8] C. Y. Lee, A. Lekich and Y. Zhang, ‘‘Perception of pitch height once a month or every two months did improve performance. in lexical and musical tones by English-speaking musicians and nonmusicians,’’ J. Acoust. Soc. Am., 135, 1607–1615 Acknowledgment (2014). This study was supported by KAKENHI Grant Number [9] M. Sadakata, L. Van der Zanden and K. Sekiyama, ‘‘Influence JP26870865 and partly by JP18H01671. A portion of this of musical training on perception of L2 speech,’’ Proc. study was presented at the Spring Meeting of the Acoustical Interspeech, pp. 118–121 (2010). Society of Japan in 2018. The procedures used in this study [10] M. Tabata, The relationship between sound sensitivity, English were in accordance with the ethical standards for human prosody processing, and English listening comprehension, experimentation proposed by the National Research Institute Dissertation submitted to Nagoya University (2015) (in of Police Science and with the Helsinki Declaration. Japanese). [11] T. C. Zhao and P. K. Kuhl, ‘‘Effect of musical experience on learning lexical categories,’’ J. Acoust. Soc. Am., 137, References 1452–1463 (2015). [1] T. Ayusawa, ‘‘Acquisition of Japanese accent and intonation [12] Y. Nakai, Keihankei Akusento Jisho (Dictionary of Keihan- by foreign learners,’’ J. Phon. Soc. Jpn., 7(2), pp. 47–58 (2003) Dialect Accentuation) (Bensei Publishing Inc., Tokyo, 2002) (in Japanese). (in Japanese). [2] N. Minematsu, ‘‘Development of an online infrastructure for [13] NHK Broadcasting Culture Research Institute Ed., Dictionary teaching Japanese prosody based on information processing of of Japanese Pronunciation and Accentuation (NHK Japan speech and text corpora,’’ J. Phon. Soc. Jpn., 19(1), pp. 18–31 Broadcasting Corporation, Tokyo, 1998) (in Japanese). (2015) (in Japanese). [14] P. Boersma, ‘‘Praat, a system for doing phonetics by [3] C. Shirota, ‘‘Perception and repeatability of Japanese accent by computer,’’ Glot Int., 5(9/10), 341–345 (2001). Tokyo and - Japanese speakers,’’ Machikaneyama [15] H. Kasuya, H. Mori and H. Kido, ‘‘Change of speaking Ronso — Japanese Studies —, 30, 27–45 (1996) (in Japanese). fundamental frequency with age,’’ Proc. Autumn Meet. Acoust. [4] A. Shirose, ‘‘Case study on the detection of native accent,’’ Soc. Jpn., pp. 281–282 (2006) (in Japanese). Proc. Spring Meet. Acoust. Soc. Jpn., pp. 589–590 (2008) (in [16] M. Sugito, Nihongo Akusentono Kenkyuu (Research on Japanese). Japanese Accent) (Sanseido, Tokyo, 1982) (in Japanese). [5] N. Tsukiji, ‘‘Building the ability of native speaking teachers to [17] N. Kibe, A. Takeda, Y. Tanaka, M. Hidaka and H. Mitsui, listen for pitch — Analysis of the difficulties of each level of Hougengaku Nyuumon, (An Introduction to Dialectology) an accent test,’’ Jpn. Lang. Educ. Methods, 15(2), pp. 30–31 (Sanseido, Tokyo, 2013), p. 37 (in Japanese). (2008) (in Japanese). [18] S. Bloomstein and W. Cooper, ‘‘Identification versus discrim- [6] T. L. Gotfried, ‘‘Music and language learning — Effect of ination of distinctive features in speech perception,’’ Q. J. Exp. musical training on learning L2 speech contrasts,’’ in Language Psychol., 24, 207–214 (1972).

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