Sonja A. Trent

Voice quality: Listener identification of African‐American versus Caucasian speakers

Although relative contributions of dialect and voice quality are difficult to tease apart, previous research has shown that listeners can perceive the gender and ethnicity of speakers at better than chance performance from recorded speech samples. The present study attempted to mitigate dialect cues and measure the resulting effects on perception by screening for dialect and by varying stimulus length. In experiment I, passages produced by ten African‐American males, ten African‐American females, ten Caucasian males, and ten Caucasian females were presented to 40 listeners with the same gender/ethnic distribution. In experiment II, sentence and citation /hVd/ stimuli produced by five of the speakers from each of the gender/ethnic groups were presented to 40 listeners. Both experiments required listeners to categorize the speakers by gender and ethnicity. Listeners were able to identify speaker gender and ethnicity at far better than chance performance. Accuracy of identification increased with stimulus le...

Context and speaker effects in the perceptual assimilation of German vowels by American listeners

To directly assess the influence of consonantal context and speaker differences on cross-language perceptual similarity of vowels, speakers of American English (AE) were asked to categorize and rate the goodness of fit of North German (NG) vowels to native categories. Four speakers produced the 14 NG monophthongs in 5 CVC contexts in a carrier sentence. Twelve listeners were presented with each speakers utterances with vowels and consonantal contexts randomly sequenced. Overall perceptual assimilation patterns showed large variations in the perceived similarity of NG vowels even for those vowels which are considered phonetically similar across languages. The front rounded NG vowels, which do not occur as distinctive phonemes in AE, were almost always assimilated to back rounded AE vowels. Significant context and speaker effects were shown for most of the NG vowels. This suggests that context-free descriptions of cross-language phonetic similarity of vowels will not be adequate in predicting relative perceptual difficulty in learning to differentiate non-native vowels. These results also have implications for theories about the nature of the representation of native-language phonetic categories.

Acoustic comparison of the effects of coarticulation on the production of Japanese and American English vowels

Cross‐language similarities and differences in the acoustic variability of vowels as a function of speaking ‘‘style’’ (citation versus sentences) and phonetic context were explored by comparing the productions of four adult male native speakers each of American English (AE) and Japanese. Multiple instances of the 11 AE vowels /i, ■, e■, e, ae, ■, ■, ■, o■, ■, u/ and the 10 Japanese vowels /i, ii, e, ee, a, aa, o, oo, ■, ■■/ produced in citation‐form bisyllables in /hVba/ and in CVC syllables /bVb, bVp, dVd, gVg, gVk/ imbedded in a carrier sentence were analyzed. Formant values at three temporal locations within the vocalic nucleus (25%, 50%, 75%) of the CVC syllables were compared with ‘‘canonical’’ /hVba/ values to determine the amount of ‘‘target undershoot’’ and changes in dynamic formant structure as a function of consonantal context. Vocalic durations were measured to determine the extent to which speaking style and consonantal context influenced relative vowel length information in the two language...

Perceptual assimilation of North German vowels to American English categories

Perceptual assimilation of NG vowels to AE categories was assessed with stimuli in which the vowels occurred in /hVp/ syllables spoken in citation form and in the sentence, ‘‘Ich habe /hVp/ gesacht.’’ Subjects were presented multiple tokens of 14 NG vowels produced by 4 male talkers. They selected the AE vowel category to which the NG vowel was most similar and rated its goodness‐of‐fit on a 7‐point scale from ‘‘English’’ (7) to ‘‘foreign‐sounding’’ (1). ‘‘Identical’’ vowels (transcribed as the same across languages) did not necessarily assimilate to the predicted category. ‘‘New’’ front rounded vowels /y, Y, o/,œ/ assimilated to back rounded AE vowels. Perceptual goodness‐of‐fit was not always predicted from the phonetic description or acoustic similarity in F1/F2 space [B. H. Fitzgerald et al., J. Acoust. Soc. Am., this session]. Differences in modal identification response and goodness‐of‐fit were noted across citation versus sentence context and across individual speakers. Assimilation on the basis of...

On what it takes to predict perceptual difficulty in cross‐language vowel perception

According to current models of cross‐language speech perception and second language (L2) speech learning, perceptual difficulty depends upon how listeners map the phonetic segments of the foreign language onto their native language (L1) categories. A number of indirect methods have been suggested for predicting perceptual difficulty, e.g., contrastive phonemic analyses and acoustic comparisons of L1 and L2 sounds. This presentation summarizes recent studies which directly assessed perceptual assimilation patterns for North German vowels (as perceived by American English listeners) and for British English vowels (as perceived by Danish listeners). Vowels were produced in CVC syllables in various consonantal contexts in both citation form and sentence frames. As expected, contrastive phonemic analyses were not good predictors of assimilation patterns. Somewhat surprisingly, acoustic comparisons didn’t always predict assimilation patterns either. In particular, measures of acoustic similarity from ‘‘canonica...

Acoustic specification of North German vowels produced in citation and sentence contexts

As part of a larger study of the effects of speech style and consonantal context on the acoustic specification and cross‐language perceptual similarity of vowels, this study examined differences in acoustic parameters of North German (NG) vowels in hVp syllables produced in citation‐form (as lists) and in the carrier sentence ‘‘Ich habe—gesacht.’’ Two instances of each of 14 vowels produced by 4 male speakers (Kiel dialect) spoken in each context were analyzed. Vowel formant frequencies (measured at syllable midpoint) showed some undershoot of F1 in sentence context relative to citation context; F2 undershoot was minimal. Duration differences between spectrally similar tense‐lax pairs varied as a function of vowel height in both citation and sentence contexts. Overall, tense‐lax duration differences were reduced in sentence context relative to citation form. Individual differences across speakers in both F1/F2 targets and intrinsic durations were noted. Distances in F1/F2 space could not account for perce...

Consonant context affects perceived similarity of North German and American English vowels

Several current theories of L2 learning attempt to predict relative difficulties in learning to produce phonetic contrasts of a foreign language on the basis of the non‐native phones’ phonetic similarity to native phoneme categories. In this study, monolingual speakers of American English (AE) were asked to categorize (into AE vowel categories) instances of the 14 North German (NG) vowels and to judge their goodness‐of‐fit on a seven‐point scale. Multiple tokens of each vowel were produced in /C‐vowel‐t/ syllables (where C=/b,d,g/) in a carrier sentence. Results indicated that both the proportion of assignments to particular AE categories and the goodness‐of‐fit ratings were influenced significantly by the initial consonantal context. While front rounded NG vowels were categorized more often overall as back rounded AE vowels than as front unrounded AE vowels, front unrounded responses were significantly greater for front rounded vowels in labial context than in alveolar and velar contexts. In addition, th...

Acoustic characteristics of American English vowels produced by Floridian female speakers

The present study analyzed the temporal, spectral, and dynamic acoustic characteristics of 11 American English (AE) vowels /i, ɪ, e, e, ae, ʌ, ɑ, ɔ, o, ᴜ, u/. The stimuli were produced by 22 monolingual female adult speakers from Florida. The vowels were embedded within the hVd consonantal context in a carrier phrase. Acoustic measurements included vowel duration, fundamental frequency, temporal midpoint and dynamic information. LPC formant contours were measured by the 25%, 50%, and 75% points of the vocalic nuclei. A perceptual vowel identification task was included in the study. Twenty Floridian female adult listeners categorized the 253 vowel stimuli using an interactive, self‐paced computer program. Results of acoustic vowel space, spectral movement, discriminant function analysis, and perceptual identification will be presented. [Work supported by NIDCD.]

Perceptual assimilation of Japanese vowels by American English listeners: effects of speaking style

Our previous research on perceptual assimilation of non‐native vowels to native categories showed that patterns of spectral and temporal assimilation vary with speaking style (citation vs sentence) and consonantal context. Japanese (J) listeners’ perceptual assimilation of American English (AE) long and short vowels to long (2‐mora) and short (1‐mora) categories was more consistent when the target syllables were presented in sentences (Strange, et al. ATR Technical Report, TR‐H‐218, 1997). In the present study, AE listeners categorized 4 speakers’ tokens of 10 J vowels /ii, i, ee, e, aa, a, oo, o, uu, u/ into 11 native AE categories and rated their goodness‐of‐fit on a 7‐point scale (7 = native). Results indicated that patterns of temporal assimilation of the J short vowels /e, a, u/ differed with speaking style. Assimilation of /e/ to mid or high front spectral AE categories also varied with context and individual speakers. Goodness‐of‐fit ratings suggested that all 10 J vowels were considered relatively...

Perceptual assimilation of German vowels by American listeners: Context and speaker effects.

This study investigated American English (AE) speakers’ perceptual assimilation of North German (NG) vowels spoken in 5 CVC contexts by four adult male speakers. Fourteen NG vowels were produced in /bVp, bVt, dVt, gVt, gVk/ syllables in the sentence ‘‘Ich habe CVC gesacht.’’ Twelve monolingual AE listeners were tested on each speaker’s corpus; consonantal context was a within‐subjects variable. Response categories were indicated by /hVd/ key words and IPA symbols. Listeners responded by selecting the AE category containing the vowel most similar to the one in the utterance and rating its ‘‘goodness of fit.’’ The percentages of selection of the modal AE response category for each NG vowel ranged from 99% for /i/→/i/ (best fit) to 41% for /o//→/u/ (worst fit). NG front and back rounded vowels were assimilated to AE back rounded vowels. However, for seven vowels, modal category percentages differed by greater than 15% across the five consonantal contexts. There was also significant variation in assimilation ...