Elaina M. Frieda

Adults' perception of native and nonnative vowels: Implications for the perceptual magnet effect

Two experiments were conducted to evaluate the perceptual magnet effect. In Experiment 1, Amer-ican English speakers representing diverse dialects were presented with a fine-grained set of stimuli (varying in just noticeable differences forF1 andF2) and indicated whether they heard “/i/” or “not /i/,” thus delimiting the /i/ portion of the vowel space for individual subjects. Then these same subjects selected their own /i/ prototype with a method-of-adjustment procedure. The data from this experiment were used to synthesize customized prototype and nonprototype stimulus sets for Experiment 2. In Experiment 2,24 of our original 37 subjects completed a discrimination task for each of three conditions, in which vector stimuli varied from the subject’s prototype, the nonprototype, or a foreign vowel (/y/) in 15-mel steps. Subjects displayed higher discrimination, as indexed byd′, for the nonprototype condition than they did for both the prototype and the foreign conditions. In addition, discrimination was better for variants further away from the referent in each condition. However, discrimination was not especially poor for stimuli close to subjects’ individual prototypes—a result that would have yielded the strongest support for the operation of a magnet effect. This negative finding, together with other aspects of our results, raises problems for any theory of vowel perception that relies solely on “one-size-fits-all” prototype representations.

Acquisition of dialectal differences in English by native Japanese speakers

Many previous investigations of second language (L2) learning have focused on the acquisition of phonetic segments by groups of non‐native speakers living in diverse regions in the US. These studies have not, however, assessed possible dialectal variation in L2 productions. The current study investigates the extent to which dialectal differences found in the vowel systems of two different American English (AE) dialects are acquired by adult Japanese speakers. Four subject groups were identified: native English speakers of a midwestern dialect of AE, native English speakers of a southern dialect of AE, Japanese speakers whose target language is a midwestern AE dialect, and Japanese speakers whose target language is a southern AE dialect. Subjects were recorded saying word and nonword utterances in isolation. Acoustic measures of vowels that can potentially capture differences between the dialects were made. These include vowel duration, and F0, F1, F2, and F3 frequencies measured at five equal distances throughout the vowel. F0–F3 measurements were used to calculate bark differences. Preliminary findings suggest that adult Japanese learners acquire some of the acoustic properties that are consistent with the dialect of the target language. [Work supported by an INRS Award from research funding from ATR (Fox, P.I.).]

Production and perception of American English vowels in different consonantal contexts by native Japanese speakers

This is a follow‐up study to our previous work on the discriminability and perception of American English vowels by native Japanese speakers. Native Japanese speakers’ production of English vowels was compared to their perception. Participants were recorded saying English words and nonwords with varying CVC contexts with a delayed repetition task in order to assess vowel intelligibility. The accuracy of their productions was assessed by native English listeners to determine whether their utterances were perceived as intended. In general, vowels that were difficult for Japanese speakers to differentiate in perception were also difficult to differentiate in production. In keeping with our previous perceptual results, the effect of consonantal contexts also played a significant role in production. For instance, Japanese speakers discriminated /ae/ better when it was preceded by velar stops and their production of these same CVs received higher identification rates. Further, /≳/‐/■/ was a difficult perceptual ...

Perceptual similarity of American English and Japanese vowels for native speakers of American English and Japanese

Native speakers of American English and Japanese chose American English vowels that best represented Japanese vowels uttered in two different consonantal contexts. The two groups of subjects’ responses differed noticeably, showing the effects of linguistic experience. The Japanese subjects tended to match Japanese long two‐mora vowels with long, tense vowels and short one‐mora vowels with short lax vowels, but the English subjects were relatively unaffected by durational differences. The Japanese subjects matched /a/ and /e/ to /ae/ and /[g\/]/, respectively, but the English subjects matched /a/ with /■/ or /■/, and /e/ with /■/ as well as /[g\/]/. The Japanese subjects matched /o/ with /■/, while the American subjects matched it with /o■/. The Japanese subjects took part in two other experiments. They equated American English vowels to Japanese vowel categories and they also identified American English vowels. They equated English /■/ to Japanese /a/, and /■/ was often misidentified as /ae/. The results of...

Perception of Japanese mora nasal /N/ and mora obstruent /Q/ by native Japanese and English speakers

Japanese mora nasal /N/ and more obstruent /Q/ have no definite point of articulation. For instance, /N/ becomes [m] when a bilabial consonant follows and [n] when an alveolar consonant follows. /Q/ is also realized as [p], [t], or [k], depending on the point of articulation of the following consonant. Four native speakers of Japanese produced /N/ and /Q/ in /CVNCV/ and /CVQCV/ contexts, where the consonant after /N/ and /Q/ is always a stop. Their utterances were recorded and digitized. The word final /CV/ was edited out, and the stimuli with the structure of /CVN/ and /CVQ/ were created. Twelve native speakers of Japanese and American English were recruited as listeners in Shiga, Japan and Auburn, AL, respectively. The American listeners were told to identify the word final consonant in a multiple‐choice format. The Japanese listeners were told that they were to tell whether /Q/ and /N/ were realized as [m], [n], [■], and [p], [t], [k], respectively. The American listeners outperformed the Japanese list...

Production and perception of American English vowels by native Japanese speakers

Native speakers of Japanese (NJ) produced American English vowels in /CVC/ contexts. Twelve native speakers of American English listened to and identified the vowels in the Japanese speakers’ productions. In general, the vowels difficult for the NJ subjects to disambiguate in production were also difficult for them to differentiate in perception. An acoustic analysis revealed that the NJ speakers’ attempted /i/ and /■/ tokens and /■/ and /■/ tokens largely overlapped in the vowel space, but significant differences in duration were observed between their /i/ and /■/ tokens. These findings agree with the results of our previous studies. In our perception experiment, /■/‐/■/ was the most difficult vowel contrast for the same group of NJ speakers to discriminate, and longer /i/ tokens were more correctly identified and shorter /i/ tokens were misidentified more often as /■/. In contrast to the perception experiment, the intelligibility of American English vowels produced by the NJ subjects was not affected by...

Identification of American English vowels by native Japanese speakers: Talker‐and‐token‐based analysis

Native speakers of Japanese identified American English vowels /i, I, e, ae, ■, ■/ produced by four female native speakers of American English in /CVC/ contexts. Native speakers of American English served as the control group, and they outperformed the Japanese subjects in identifying all the English vowels in every /CVC/ context. In another experiment the Japanese subjects equated these English vowels with Japanese vowels. In general, English vowels were equated with phonetically close Japanese vowels, but significant talker effect was observed. The /i/ tokens equated with the Japanese long high front vowel /ii/ were much more correctly identified as /i/ than those equated with the Japanese short high front vowel /i/. These tokens were more often misidentified as /I/. The /■/ and /■/ tokens were predominantly equated with the Japanese low vowel /a/. The percent‐correct identification of /■/ and /■/ was low in most of the /CVC/ contexts, and these two vowels were often misidentified as each other, and the ...

Discriminability and identification of English vowels by native Japanese speakers in different consonantal contexts

The purpose of the present experiment was to examine the effects of consonantal context on discrimination and identification of English vowels by native Japanese speakers learning English in Japan. A number of studies have assessed the effects of consonantal contexts on the perception of nonnative vowels. For instance, Strange et al. (1996, 2001) found that perceptual assimilation of nonnative vowels is affected by consonantal contexts, and Morrison (2002) has shown that Japanese speakers use durational cues to perceive English /i/–/I/. The present study revealed that consonantal context affects discriminability and identification of each English vowel differently. Of all the six vowel contrasts tested, /i/–/I/ was the most likely to be affected by voicing status of the surrounding consonants with it being easier to discriminate in voiceless consonantal contexts. Moreover, /I/ is more likely to be equated with the Japanese short vowel /i/ in a voiceless consonantal context which is in keeping with Morriso...

The effects of regional dialect on vowel intelligibility from a cross‐linguistic perspective

The present experiment is a continuation of a previously reported study that examined intelligibility of English vowels as a function of dialect spoken by native speakers of English and Japanese. The purpose of this research is to assess how regional dialectal variations affect vowel intelligibility for native and non‐native speakers of English. Native English and Japanese subjects were recorded in two divergent dialectal regions of the United States (Ohio and Alabama). These tokens were then employed in a perceptual experiment where native English and Japanese listeners from Ohio and Alabama identified the English vowels. To date, perceptual data from only Ohio native English and Japanese subjects have been reported. A further analysis of the data including Alabama native English and Japanese listeners revealed that native English speakers from Ohio obtained the highest intelligibility scores overall (for example, all four listener groups identified Ohio English more accurately than all other groups). Ad...

Effects of consonantal contexts on the perception of English vowels by experienced and inexperienced Japanese learners of English

The perception of English vowels by experienced and inexperienced Japanese learners of English in different consonantal context were compared. Experienced Japanese learners of English were recruited in Gainesville, FL and inexperienced Japanese learners of English were recruited in Kobe, Japan and vicinity. In one experiment, subjects’ ability was tested to discriminate English vowels in different consonantal contexts. What was expected to affect the discriminability was (1) voicing of the preceding and the following stops, (2) places of articulation of the preceding and the following stops, and (3) nasality of the following consonant. In another experiment, the subjects identified English vowels in terms of Japanese vowel categories. Generally, English vowels identified with the same Japanese vowels were more difficult to discriminate than those identified with different vowels. In both experiments, the inexperienced learners were more susceptible to talker and consonantal context differences. [Work supp...