A Study of Japanese Learners’ Perceptual Identification of English Fricativesᝲǽ୫

A Study of Japanese Learners’ Perceptual
Identification of English Fricatives

ISONO Toruᛵǽ஖
本論文の目的は，日本人学習者の英語摩擦音に対する知覚能力を実証的に検証していくことである。摩擦音に関しては，英語摩擦音の方が日本語摩擦音よりも種類が豊富なため，日本人英語学習者の特徴として，発音面においては一つの日本語音が二つの英語音に使用され（例えば，日本語の が英語の  と  の両方に用いられる等），知覚面においてはその二つの音の判別を不得意としているという現象が広く認知されている。本研究では，日本語と英語間でそのような関係性になることが多い摩擦音において，語頭・語末そして有声音・無声音といった違いがどのように日本人学
習者の英語摩擦音に対する知覚に影響を及ぼすのかを検証していく。本研
究の被験者は英語を専攻している日本人大学生で，彼・彼女らにターゲッ
ト音を含む音声刺激を計200 回ランダムに与え，どの英語音と認識したかを答えさせた。本論文では，その正答率を検証データとして紹介し，それをもとに日本人学習者の英語摩擦音に対する知覚能力の特徴を考察していく。

キーワード：音声知覚，摩擦音，日本人英語学習者，語頭，語末，
有声音，無声音

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1. Introduction
When we compare English fricatives with Japanese ones, we can firstly see that there isa difference in the total number of fricatives. The table1 which includes both English andJapanese fricatives is shown below.
Table 1. Comparison of English and Japanese fricatives
LabialCoronalEnglish –  – ,  – ,  – Japanese – , DorsalAs shown in the table, there are a larger number of English fricatives than of Japanesefricatives. This means that Japanese learners sometimes tend to substitute one Japaneseconsonant for more than two English consonants in their English production. It has
been often discussed as the typical problems of Japanese English, since the fact that
substituting one Japanese sound for more than two English sounds makes the tolerance
level for inaccurate pronunciation lower when English native speakers listen to thepronunciation of Japanese learners, not the other way round. Recognising the reasons
why these substitutions occur is one of the most important points of studying English
production and perception by Japanese learners, so the brief description of the reasons
are outlined in the rest of this section focusing on the English  – , – , and– , which are investigated in this paper.
Both the English  and the Japanese  are classified as labial fricatives in the abovetable, and because Japanese does not have , the Japanese  tends to be substituted for
the English . However, in a narrower analysis, they are different in that the English 
is a labiodental fricative, which means the places of articulation are the lips and the teeth,
yet the Japanese  is a bilabial fricative, which indicates the place of articulation is only
the lips, and it is pronounced by protruding the lips. The fricative noise of the English 
is never very strong (Roach, 1991), but that of the Japanese  is even weaker than that.
The English  is a voiced sound of the English . However, since the corresponding
voiced sound of the Japanese  is alien to the Japanese sound systems, the Japanese which is a bilabial plosive tends to be substituted for the English  because of
the similarity in the place of articulation between the bilabial and the labiodental.
Consequently, the Japanese  tends to be substituted for both the English  and . In

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addition to the difference in the quality of noise between the English  and the Japanese(the English) : namely, the former has the feature of [friction] but the latter has [plosion],they are also different in the duration times. The duration of the English  is longer thanthat of the Japanese . This is due to the fact that fricatives are the consonants whichhave the feature of [continuant], which means, to borrow Roach’s (1991: 47) phrase, that“you can continue making them without interruption as long as you have enough air inyour lungs”, yet plosives are not continuants.
The English  –  are dental or inter-dental fricatives in which the tongue isplaced inside the teeth or between the teeth, and since Japanese does not have any interdental fricatives, the Japanese  –  tend to be substituted for the English  – .
This would be one of the most typical substitutions characterising Japanese learners’
English pronunciations, and it is often cited as the typical example supporting Lado’s(1957: 27) following statement: “When a phoneme in the foreign language does notexist in the native language the student will tend to substitute the native phoneme that
seems nearest within the whole structure of his native language”. In addition, it has been
revealed that the English  –  cause pronunciation problems not only for Japaneselearners, but also for other language learners such as Spanish, Russian and French (Lado,
1957; Ritchie, 1968), and even for English native children (Moskowitz, 1970; Asao &Tanabe, 1993).

2. Aims of Experiment
As outlined above, the relationship between English fricatives and Japanese ones
is far more complex than that between English plosives and Japanese ones, which ischaracterized by having the same repertory. Hence, there is fairly general agreementthat English fricatives are more difficult for Japanese learners to produce than English
plosives. The first aim of the experiment presented in this paper is to examine whether itis true in the case of their perception.
The second aim of the experiment is to investigate the difference in accuracy ofperception between English fricatives in word-initial position and those in word-final
position by Japanese learners. In the concept of markedness, features being simple andcommon are said to be unmarked, but those being complex and less common are said to bemarked, and the latter are basically more difficult to acquire than the former in language

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No. 42acquisition, because the latter often require more complex movements of the tongue
muscles. In past studies, it was reported that difficulty in perception varied according topositions where target sounds appeared by Koike et al. (1977, cited in Asao and Tanabe,1993). The subjects enrolled in that survey were around 900 Japanese learners who werestudying at Japanese universities. After listening to each word including a target sound,they were instructed to listen to the other four words, and then choose one of them, which
was perceived to be identical to the word previously presented. According to Asao andTanabe (1993), despite the low percentage of the correct answer for the [b] – [v] contrast,
when they were placed in word-initial position, the percentage of the correct answer
was about 90%. However, conversely, in the case of the word containing  in the wordfinal position, the accuracy rate was 95%, but it was only 51% when  was placed in
the word-initial position. Another study which examined the relationship between theaccuracy rate in perception and positions where target sounds appear was Isono (2018).
He investigated the perception of English plosives by Japanese learners, and clarified
that they had greater difficulty perceiving English ,  and  in word-final position
than those in word-initial position, although such a difference was not obtained in thecases of English , , and . The experiment presented in this paper sees whether acertain common feature is observed in the case of the perception of English fricatives byJapanese learners.
The concept of markedness can be applied to the contrast of voiced and voicelesssounds, and a voiced sound is generally regraded as more marked than a voiceless sound,because the former requires more complex muscle movements to vibrate the vocal folds.
The third aim of the experiment is to see whether voiced English fricatives are muchharder for Japanese learners to perceive than voiceless English fricatives.
In addition to the above, this paper also examines the accuracy rates on the English
sounds which are often substituted by one Japanese sound in production, such as  & , & , and  & , to see how much influence does the Japanese sound system haveon Japanese learners’ perception in English.

3. Outline of Experiment
All of the subjects taking part in Isono (2018) were also engaged in this experiment.
To sum up, they were 52 university students2 (16 first year students, 16 third year students,

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and 20 fourth year students) majoring in English at Aichi University. The experiment was
conducted using English Accent Coach (https://www.englishaccentcoach.com/), rightafter the experiment which was presented in Isono (2018).
This experiment gave the subjects the following two tasks. In Task 1, English words
having English plosives ( – ,  – , and  – ) and English fricatives ( – , – , and  – ) in word-initial position were randomly given to them 100 times,
and they were asked to identify the sound after they listened to each word. In Task 2,
English words having the above English plosives and fricatives in word-final position
were randomly given to them 100 times, and they were asked to be enrolled in the sametask. In the analysis, however, it was found that the words containing  in word-final
position had not been given to the subjects in Task 2, so the target fricatives in the task
were the above 6 plosives and the 5 fricatives ( – , , and  – ) in word-final
position.
In both tasks, only the above tested sounds were shown on the screen as the choices,
so they had to choose their answers from the above 12 sounds.

4. Analysis
Each of the subjects gave 12 responses in Task 1, which shows the percentages ofcorrect answers for each of the 6 fricatives and 6 plosives in word-initial position, and 11
responses in Task 2, which does the percentages of correct answers for the 5 fricatives
and 6 plosives in word-final position. In total, 1196 responses (52 subjects × 23 responses)
were obtained in this experiment to analyse.

4.1 Fricatives vs Plosives
The mean difference in the percentages of correct answers between fricatives andplosives is presented in the below table.
Table 2. Difference in accuracy between fricatives and plosives
Accuracy (SD)

Fricatives

Plosives

69.25% (30.43)

95.13% (9.54)

The difference in the accuracy rates between fricatives and plosives is obvious, andthe Japanese subjects had more difficulty to perceive English fricatives correctly than

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to be big differences in the perceptual performance on the tested fricatives. In the next
few analyses, we will see some characteristics of the perception of English fricatives byJapanese learners.

4.2 Word-initial vs Word-final
Next, we shall look closely at the difference in accuracy of perception between
English fricatives in word-initial position and those in word-final position by the Japanese
subjects, which is shown in the below table.
Table 3. Difference in perception of fricatives
Accuracy (SD)Word-initial position

Word-final position

68.51% (30.72)

70.08% (30.13)

We assumed that fricatives in word-final position would be more difficult to perceive
than those in word-initial position due to the markedness features, but the accuracy of
the former was a little higher than that of the latter, as the table shows. One explanation
for this phenomenon is that the perception ability of English  in word-final position,
which might have been relatively difficult for Japanese learners, was not examined in thisexperiment. However, when we look at the below table which provides the breakdown ofTable 3, we do not see there is much justice in that view.
Table 4. Perception of fricatives in word-initial and word-final position
Word-initial

Word-final



88.00% (10.88)

82.09% (27.64)



49.06% (30.70)

50.00% (36.79)



64.41% (40.11)

73.53% (28.08)



63.86% (26.08)

̶̶̶



82.23% (14.20)

80.57% (19.69)



59.28% (30.05)

63.31% (24.82)

As the figures in the above table show, significant differences in the accuracy rates
between fricatives in word-initial position and those in word-final position were notobserved. They were also not statistically obtained in all the cases of , , ,  and: t = 1.433, df = 66.44, p > .05; t = −.120, df=93, p > .05; t = −1.17, df = 58.19, p > .05;

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t = .49, df = 92.74, p > .05; and t = −.736, df = 99, p > .05. Therefore, the results are notconsistent with the assumption that English fricatives in word-final position are moredifficult to perceive than those in word-initial position for Japanese learners. In fact, it
is interesting to note that the accuracy rate on the English  in word-final position wasmuch higher than that on the English  in word-initial position. This is a point to which
we shall return later.

4.3 Voiceless fricatives vs Voiced fricatives
In this section, we turn to the verification of the assumption that English voicelessfricatives are easier for Japanese learners to perceive than English voiced fricatives.
Table 5. Differences in accuracy between voiceless and voiced fricatives
Accuracy (SD)

Voiceless fricatives

Voiced fricatives

76.08% (26.57)

62.18% (26.95)

As shown in the above table, the accuracy rates on English voiceless fricatives werehigher than those on English voiced fricatives, and the difference was statisticallysignificant (T = −4.79, df = 343, p < .01).
The below two tables show the breakdown of Table 5.
Table 6. Difference in accuracy between  and  in word-initial position
Word-initial





64.41% (40.11)

63.86% (26.08)

Table 7. Difference in accuracy between  and  in word-initial and -final position




Word-initial

82.23% (14.20)

59.28% (30.05)

Word-final

80.57% (19.69)

63.31% (24.82)

The difference is not statistically obtained between the accuracy rates on the English 
in word-initial position and those on the English  in word-initial position (t = .073, df =55.24, p > .05), but it is found between the accuracy rates on the English  and  in bothof word-initial and -final positions (T = 4.89, df = 69.23, p < .01), (T = 3.91. df = 101, p <.01), respectively. These results suggest that the above assumption is valid in some cases,
but it is not in other cases, and this is a question to be considered later.

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4.4 Perception of  – ,  – , and  – 
As noted earlier, one Japanese consonant tends to be substituted to more than two
English consonants in the production of Japanese learners due to the difference in thenumber of consonants between Japanese and English. Concerning the sounds examinedin this paper, the Japanese  tends to be substituted to both of the English  and , theJapanese  to the English  and , and the Japanese  to the English  and , and
it is difficult for Japanese learners to distinguish the differences of the sounds in theirEnglish perception. In this section, we see how much the above English sounds weresuccessfully distinguished by the Japanese subjects.
Table 8. Differences in accuracy between  and 




Word-initial

90.09% (8.01)

49.06% (30.70)

Word-final

87.90% (20.45)

50.00% (36.79)

The above table shows that the accuracy rates on the English  were quite high, but
those on the English  were about 50%, which means the probability was only one-half,in both cases of word-initial and -final positions. This result suggests that the Japanese
subjects were not able to distinguish the English  from the English  successfully, andeven when the English  was given to them, it tended to be perceived as the English .
The same tendency was observed in the relationship between the English  and theEnglish  in word-initial position as presented in the below table. The number for the
English  was better than a 50% chance, but a significantly big difference was obtained
between the two.
Table 9. Differences in accuracy between  and 




Word-initial

82.23% (14.20)

64.41% (40.11)

Word-final

80.57% (19.69)

73.53% (28.08)

However, in the case of the English  and  in word-final position, the accuracy rates
were high in both, and we see that it was relatively easy for the Japanese subjects todistinguish the English  from the English  when they appeared in word-final position.
Finally, we shall investigate the case of the English  and .

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A Study of Japanese Learners’ Perceptual Identification of English Fricatives
Table 10. Differences in accuracy between  and 




Word-initial

59.28% (30.05)

63.86% (26.08)

Word-final

63.31% (24.82)

̶̶̶Unlike in the previous cases, despite the fact that Japanese has the corresponding sound in its sound system, it was clarified that the Japanese subjects had difficulty inperceiving the English  correctly, let alone the English .
In the next section, we shall examine the reasons of the phenomena which wereobserved in this experiment.

5. Discussion
The experiment investigated the perception of English fricatives by Japaneselearners mainly focusing on the following four points: 1. The difference in the accuracy
rates between English fricatives and English plosives; 2. The difference in the accuracy
rates between English fricatives in word-initial position and those in word-final position;
3. The difference in the accuracy rates between voiceless English fricatives and voiced
English fricatives; and 4. The effect of the Japanese sound system on Japanese learners’
perception in English. In this section, we discuss the results of the last three points.
Concerning the above second point, significant differences were not observed
according to the position of the English fricatives. To sum up, the accuracy rates on the
English  and  were high, but those on the English  and  were relatively low, nomatter whether they appeared in word-initial position or in word-final position. This
result suggests that the accuracy rates on the fricatives which are easy for Japaneselearners to perceive are high, but those which are relatively difficult are low, regardlessof the position in which they are placed. One more point to observe is that the accuracy
rates on the English  in word-final position were higher than those on the English 
in word-initial position. In fact, the same tendency was reported by Koike et al. (1977,
cited in Asao and Tanabe, 1993). The reason could be attributed to the effect of the soundfollowing the English . Comparing the case that the English  is followed by a vowel
in word-initial position with the case that it is not followed by any sound in word-final
position, the latter case might be easier for Japanese learners to distinguish the differenceof fricative noise between the English  and .

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As for the third point, the experiment showed that the English voiced fricatives weremore difficult for Japanese learners to perceive than the English voiceless fricatives.
It is true that there is room for further investigation in this issue, because significant
differences were not found between the English  and . However, when we take theresults obtained by Isono (2018) who investigated English plosives into consideration withthis result, it seems reasonable to suppose that English voiced consonants are basicallymore difficult for Japanese learners to perceive than English voiceless consonants. A
difference between the English  –  and the other sounds, such as English plosives
and the English  – , is that the former are new sounds for Japanese learners, but thelatter are not. As outlined earlier, the Japanese sound system does not have any soundcorresponding to the English  – , but it has  – ,  – ,  – , and  – .
One possibility is to assume that the difference of voiceless-voiced consonants may
not affect the perception of “new” L2 consonants, simply because they are difficult forlearners to perceive no matter whether they are voiceless or voiced sounds.
Finally, the results of this experiments generally supported the assumption thatL2 learners’ perception is conditioned by their L1 sound systems. However, we should
not overlook that the accuracy rates on the English  were low in both of word-initialand -final positions. Although it is noted earlier that the Japanese sound system has thecorresponding sound to the English , the conclusion that the corresponding voiced
sound of the Japanese  is  is open to objection. The variation and the distribution of
the Japanese  are quite complicated as outlined in Fujii (1999), but the characteristics
summarized into the three points below would be now relatively widely accepted.
1. The Japanese  has two allophones  and .
2.  occurs when the Japanese  is in word-initial position before , , ,3. On the other hand, when it is in word-medial position or is pronounced very
weakly, before the vowels, it is sometimes realized as .
3.  occurs when the Japanese  is in word-initial position before 4. However,when it is in word-medial position or is pronounced very weakly, before , it issometimes realized as .

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Since  and  are perceived as much more typical Japanese sounds than  and ,Japanese learners of English tend to substitute the Japanese  for the English , andthe Japanese  for the English  (Igarashi, 1981; Imai, 1983). It seems reasonable tosuppose that the above complex relationship between  and other sounds might haveaffected the result of this experiment, and it suggests that we must pay more attention to
the difficulty of perceiving the English  by Japanese learners in educational scenes.
Notes
1
2
3
4

The framework of this table is made mainly referring to Ladefoged’s (1993) viewpoint ofclassification.
One subject was not able to participate in the experiment presented in this paper, so the subjects
were one person fewer than those who took part in Isono (2018).
Jyouo (1992) notes that the Japanese  is also realised as  after [N].
According to Imai (1983), in the case of loanwords, when the Japanese  precedes , it is also
realised as .

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