Vowel Quality Differences Research Articles

What does it mean to sound Korean-Canadian, eh? A comparative study on Canadian English vowel space

Existing research on Canadian English shows evidence of dialectal differences between regions. Not only are there differences based on region, but groups (e.g., heritage, immigrant) in these respective regions are not participating in the ongoing sound changes of Canadian English (e.g., Canadian Raising) to the same degree. In respect to sound changes, studies have found that some sounds are undergoing more drastic change than others, young female groups are usually more advanced in the progress, and that the largest heritage groups in major Canadian cities (Toronto, Vancouver, Montreal) are participating in sound changes—with some reported differences in vowel quality. This study extends the existing literature on Canadian sound changes by investigating the acoustic vowel quality of Korean heritage speakers in Vancouver. The speech of 11 monolingual Canadian English speakers and 22 Korean heritage speakers were analyzed for specific sound patterns (/u/-fronting, /æ/ raising) as well as overall vowel space area. This study finds that Korean heritage speakers also participate in the ongoing sound changes (e.g., /u/-fronting) but there are also some notable differences in their vowel acoustics, when compared to their monolingual counterparts.

The sounds of Japanese English: Monophthong vowels and rhythmic patterning

ABSTRACT This article offers finer-grained acoustic analyses of two aspects of the linguistic sound system of Japanese English (JpE): monophthongal vowels and rhythmic patterning. At the segmental level, though past research has examined the vocalic inventory of JpE, these studies have tended to focus on vowel quality differences in the acoustic space. Our study approaches the acoustic investigation of monophthongal vowels in JpE by examining not just vowel quality, but also vowel duration. At the level of prosody, we conduct a quantitative analysis of the rhythm of JpE using the pairwise variability index. Results suggest that monophthongal vowels in JpE do not exhibit a homogeneous pattern of ‘conflation’ in terms of vowel quality or duration, and that JpE tends towards a stress-timed patterning of speech rhythm. Hence, the empirical data argue for the need of a ‘pluricentric’ paradigm to undergird world Englishes research, rather than a ‘monolithic’, Inner Circle norm-centric framework.

Vowels and tones as acoustic cues in Chinese subregional dialect identification

The aim of the present perceptual study is to weight tones and vowels as acoustic cues in Chinese subregional dialect identification, and to test the credibility of the subregional dialect classification that has been proposed in the literature. Our findings show that listeners are able to pinpoint speakers’ subregional dialect even when only given monosyllabic Chinese word stimuli, either natural or tone-transplanted. The results agree with the impressionistic claim that both vowels and tones contribute to perceptual subregional dialect identification. However, vowel quality differences make a greater contribution than the tone differences – which contradicts the order of importance predicted in the impressionistic literature. Strong interactions between vowels and tones are also found.

Perceiving Southernness: Vowel categories and acoustic cues in Southernness ratings.

Southern U.S. speech has been the focus of much sociophonetic work. In terms of vowel patterns, Southern speech is often characterized by the Southern Vowel Shift (SVS, involving shifts in /e/, /ɛ/, and /aɪ/), back vowel fronting, and changes in glide dynamics. The SVS, in particular, is said to play a primary role in distinguishing the South as a unique dialect region. However, there have been few investigations of the role of various vowel quality differences in perceptions of Southern accent, particularly across the vowel space beyond /e/, /ɛ/, and /aɪ/, or that ask whether any aggregate speaker-level acoustic measures align with listeners' perceptions, despite some suggestions in the literature to this effect. The current study examines what acoustic cues contribute to non-Southern listeners' evaluations of words spoken by Southerners as sounding more or less Southern accented, looking at a range of vowels from across the vowel space. Results indicate that listeners rate the speakers' productions of /u/ and /ɔ/ as most Southern and that vowel dynamics and speaker-level measures were the acoustic factors most predictive of Southernness ratings. These results together call for further work examining vowel dynamics and a more complete set of vowel categories in perception studies of Southern speech.

The Perception of Cantonese Vowel Length Contrast by Mandarin Speakers.

The study investigates the perception of vowel length contrasts in Cantonese by native Mandarin speakers with varying degrees of experience in Cantonese: naïve listeners (no exposure), inexperienced learners (~1 year), and experienced learners (~5 years). While vowel length contrasts do not exist in Mandarin, they are, to some extent, exploited in English, the second language (L2) of all the participants. Using an AXB discrimination task, we investigate how native and L2 phonological knowledge affects the acquisition of vowel length contrasts in a third language (L3). The results revealed that all participant groups could discriminate three contrastive vowel pairs (/aː/-/ɐ/, /ɛː/-/e/, /ɔː/-/o/), but their performance was influenced by the degree of Cantonese exposure, particularly for learners in the early stage of acquisition. In addition to vowel quality differences, durational differences were proposed to explain the perceptual patterns. Furthermore, L2 English perception of the participants was found to modulate the perception of L3 Cantonese vowel length contrasts. Our findings demonstrate the bi-directional interaction between languages acquired at different stages, and provide concrete data to evaluate some speech acquisition models.

Quasi-phonemic vowels in Ampenan Sasak: An acoustic analysis

Phonological studies on Sasak tend to agree that Sasak has a six-vowel system /i, u, e, o, ə, a/ (Archangeli et al., n.d.; Chahal, 1998; Jacq, 1998). However, in Ampenan Sasak, a dialect spoken in the provincial capital of Mataram, it is difficult to attribute vowel quality differences of tense mid-vowels [e, o] and lax mid-vowels [ɛ, ɔ] to allophonic variation of underlying phonemes /e, o/. While lax mid-vowels tend to appear in heavy syllables and tense mid-vowels appear in light syllables (see also Archangeli et al., n.d.), there are exceptions (e.g., /baɾeh/ late, /əmbong/ reservoir) and several minimal pairs (e.g., /bəɾəmbok/ discuss, /bəɾəmbɔk/ breathe; /koboʔ/ levening, /kɔbɔʔ/ play with water). Further, speakers’ intuitions about these distinctions are unreliable. In order to understand this relationship, we elicited wordlists across 13 female speakers of Ampenan Sasak aged 18 to 48. Wordlists were balanced for syllable weight, coda segment, and syllable position and subjected to acoustic analysis. Preliminary results show that the quality of the vowel is highly affected by the weight of the syllable and the coda segment. This suggests that mid-vowels are quasi-phonemic in Ampenan Sasak (Ladd 2013). While they generally behave as allophones, this paradigm is not strictly followed.Phonological studies on Sasak tend to agree that Sasak has a six-vowel system /i, u, e, o, ə, a/ (Archangeli et al., n.d.; Chahal, 1998; Jacq, 1998). However, in Ampenan Sasak, a dialect spoken in the provincial capital of Mataram, it is difficult to attribute vowel quality differences of tense mid-vowels [e, o] and lax mid-vowels [ɛ, ɔ] to allophonic variation of underlying phonemes /e, o/. While lax mid-vowels tend to appear in heavy syllables and tense mid-vowels appear in light syllables (see also Archangeli et al., n.d.), there are exceptions (e.g., /baɾeh/ late, /əmbong/ reservoir) and several minimal pairs (e.g., /bəɾəmbok/ discuss, /bəɾəmbɔk/ breathe; /koboʔ/ levening, /kɔbɔʔ/ play with water). Further, speakers’ intuitions about these distinctions are unreliable. In order to understand this relationship, we elicited wordlists across 13 female speakers of Ampenan Sasak aged 18 to 48. Wordlists were balanced for syllable weight, coda segment, and syllable position and subjected to aco...

Cross-dialect and cross-language differences in perception of vowels: A multidimensional scaling study

This study examines the perceptual responses to vowels in two regional varieties of American English typical of Central Ohio (OH) and Western North Carolina (NC). Listeners are monolingual local speakers of each dialect and Mandarin-English bilinguals in Columbus OH. The questions are (1) how English listeners perceive acoustic variations in vowel quality differences not found in their own dialect and (2) whether bilingual listeners are sensitive to such differences not found in their native language. In a multidimensional scaling study, we investigate whether listeners make these perceptual decisions on the basis of acoustic properties or categorical properties of these vowels. Each listener was presented with two sets of 13 vowels /i ɪ e ɛ æ u ʊ o ɔ ɑ ɔɪ aɪ aʊ/ in a /hVd/ syllable. One set was produced by an OH male speaker and the other by a NC male speaker. Listeners rated all possible vowel pairs from one set only on a nine-point similarity/dissimilarity scale (there were two subsets of listeners in each group). The resulting dissimilarity matrices were analyzed using INDSCAL. Results will be discussed in terms of differences in perceptual dimensions (vowel coordinates and subject weights) as a function of dialect and L2 background.

Sub-phonemic correlates of gender and regional identity in California

Given that the Northern and Southern California have large metropolitan areas geographically and culturally separated from each other, it is to be expected that each is developing a unique linguistic identity. Despite a handful of ethnographic studies showing otherwise (e.g., Hall-Lew 2009), the West has generally been lumped into a single dialect region (Labov etal. 2006). This paper presents data showing sub-phonemic differences between the regions that break along gender lines. Vowel productions from 14 (female = 8) Northern Californians (NCs) and 15 (female = 8) Southern Californians (SCs) were analyzed for regional differences in normalized vowel quality, voice quality (spectral tilt), pitch, and duration. No major differences in vowel quality were found. However, interactions were found between region and gender for duration and voice quality. Specifically, NC females had significantly longer word durations than NC males, with no difference between genders for SC. For voice quality, H1-H2 and H1-A3 measures both demonstrated significant differences between males and females for SC, with female voices being breathier, but with no differences for NC. Currently, a perception experiment is underway to determine if listeners can use these differences to categorize voices by region.

Active change in American English dialects and their role in age perception.

Prior studies on vocal aging have varied with respect to the perceptual relevance of vowel formants. Two patterns have been (inconsistently) observed: formant lowering due to age-induced laryngeal lowering and formant centralization. A third hypothesis was investigated here: that active changes in the vowel systems of American English dialects, lead by younger (especially female) speakers, can themselves serve as vocal age cues independent of the cited (physiological) changes. One active vowel change is the California vowel shift, involving the lowering/backing of [I], [E], and [ae], one that has also been observed in young speakers in Florida and elsewhere. Would such systematic differences in vowel quality occurring frequently in younger speech play a significant role in female voice age perception? Speech samples were collected from 20 young and 20 middle-aged female residents of northern Florida under four conditions: (a) while conversing with another speaker matched versus mismatched in age category and (b) having been trained (versus untrained) to accurately simulate the California vowel shift in younger speakers. Acoustic analysis and age estimation studies were conducted to determine if the presence of a natural/simulated “younger” dialect shifted perceived age and the extent of any shift relative formant lowering and formant centralization.

Regional dialect variation in standard Italian.

Italy is a linguistically diverse country where a standard language (standard Italian) is in contact with various regional languages. Within this setting, the regional languages have influenced the standard Italian spoken throughout Italy and regional dialects of Standard Italian have emerged. Previous studies on the regional dialects of Standard Italian have predominantly taken a descriptive approach to discussing the phonological differences between the dialects and a broad acoustic study of the dialects is lacking. The present study seeks to identify several acoustic characteristics of regional varieties of spoken standard Italian. In the study, an acoustic investigation of vowels produced by male and female talkers from Northern, Central, and Southern Italy was carried out. Acoustic measures obtained included vowel duration and first and second formant frequencies. These measures were used to examine possible dialectal differences in vowel quality, vowel duration, and the overall acoustic vowel space. From these measures, several dialect‐specific phonetic features were identified. These dialect‐specific acoustic properties will be discussed. The results of the acoustic analysis will serve as a basis for future studies investigating the acoustic properties of the regional varieties of standard Italian and for identifying the types of cues listeners might use to distinguish the dialects.

A Phonological and Phonetic Study of Word‐Level Stress in Chickasaw

This paper presents results of a phonological and phonetic study of stress in Chickasaw, a Muskogean language spoken in south central Oklahoma. Three degrees of stress are differentiated acoustically, with primary stressed vowels having the highest f 0 and greatest duration and intensity, unstressed vowels having the lowest f 0 and shortest duration and intensity, and secondary stressed vowels displaying intermediate f 0, duration, and intensity values. Vowel quality differences and segmental lenition processes also are diagnostic for stress. The location of stress is phonologically predictable, falling on word‐final syllables, heavy (CVC and CVV) syllables, and on the second in a sequence of light (CV) syllables. Short vowels in nonfinal open syllables are made heavy through a process of rhythmic vowel lengthening. Primary stress is sensitive to a further weight distinction, which treats CVV as heavier than both CV and CVC. In words lacking a CVV syllable, stress falls on the final syllable.

Perception of different speech registers in noise

Infant-directed speech and adult-directed clear speech both exhibit acoustic characteristics (other than amplitude differences) which should make them easier to perceive against a background of noise than adult-directed conversational speech. For example, in adult-directed clear speech, vowels are typically acoustically more distinct. Infant-directed speech shows similar differences in vowel quality, and in addition typically shows larger pitch contours. This experiment examines listeners’ perception of these three speech registers (adult-directed conversational speech, adult-directed clear speech, and infant-directed speech) in noise. Effect of the different speech registers will be compared for easy words (frequent words with few frequent lexical neighbors) and hard words (infrequent words with numerous, frequent neighbors).

Black South African English: A new English? Observations from a phonetic viewpoint

This study investigates the extent to which users of Black South African English (BSAE) command the vowel system of English. One mother‐tongue speaker each of English, Southern Sotho and Zulu read a set of stimulus words representing various monophthong contrasts in standard South African English. Three groups of subjects participated as listeners in an experiment on English vowel perception. These include (1) 21 Southern Sotho speakers and 21 Zulu speakers, (2) 41 Arabic speakers, and (3) 20 Afrikaans speakers. The Arabic and Afrikaans speakers were used in the experiment for comparative purposes. Overall the results indicate a general lack of command of the vowel contrasts of Standard South African English by the speakers of Bantu languages. The same holds but to a lesser extent for the other two groups of listeners. Further analysis reveals that the Southern Sotho‐ and Zulu‐speaking listeners process the long vowel/short vowel contrast differently from contrasts based on vowel quality differences. In the concluding section, the results are interpreted against the backdrop of current theories of second language acquisition. The evidence supports transfer‐based explanations for phonological acquisition, since the vowels that the first language and target language of the speakers share are perceived more accurately than those that the languages do not share. In addition, the results are discussed in relation to the question whether BSAE is an interlanguage, or a fully‐fledged new English. On the face of current evidence, it seems that the mesolectal form of BSAE could be viewed as an interlanguage rather than as a new English, but one that has as yet to develop into a more stable alternative to the standard variety of South African English.

An interactive atlas of English vowels: Design considerations

Discussions of vowel quality differences in dialects of English are often based on imprecise, subjective descriptors (more open, slightly less back) and transcriptions rather than instrumental measurements. Available instrumental data focus on individual dialects rather than a broader picture of dialectal variation. In part to address these concerns, a database of vowel formant frequencies is currently being developed at the University of Washington, beginning with a sampling of static formant frequencies in the American West. The ultimate intent is to produce a web-based, expandable database, or atlas, of reference English vowel formant frequencies and audio examples. It is intended primarily as a pedagogical tool to accurately demonstrate vowel quality variation, and as a ‘‘jumping off point’’ for more intensive studies of acoustic variation. This poster discusses long- and short-term goals of the project, current data, the standardized methodology being used, web tools being developed, and the possibilities for future collaboration in data collection and analysis.

Acoustic and auditory evidence of sociophonetic variation in Vancouver: LTAS and vocalic data.

Formant frequencies of ten Canadian English vowels from identical environments in reading style were calculated for 128 subjects in the middle and older age groups of the sociolinguistic Survey of Vancouver English. LPC-based F1, F2 distributions were derived using a computerized speech lab (CSL) program and evaluated statistically to identify differences in vowel quality across four socioeconomic-status (SES) classes for both sexes. Long-term average spectra (LTAS) of 60 s of reading text were also computed and compared with vowel formant results. The SDDD LTAS dissimilarity index (standard deviation of the differences distribution) was also applied to the 192 subjects in all (including young) age groups. Auditory evaluations of each subject’s production of each vowel were compared with the results of formant analysis and both LTAS analyses. Here, F1 values were more uniformly differentiated than F2, and some groups’ vowels were more vulnerable to rejection of F2 on bandwidth criteria than others. Differentiation is significant and consistent for a high proportion of vowel formant distributions for some SES groups, notably between working-class (WC) and middle-class (MC) middle-aged women. Some F1, F2 patterns are compatible with auditory predictions of a hierarchy of vocalic susceptibility to contrasting voice quality settings. [Work supported by SSHRCC.]

An approach to the problem of regional accent in automatic speech recognition

An approach to the problem of inter-speaker variability in automatic speech recognition is described which exploits systematic vowel differences in a two-stage process of adaptation to individual speaker characteristics. In stage one, an accent identification procedure selects one of four gross regional English accents on the basis of vowel quality differences within four calibration sentences. In stage two, an adjustment procedure shifts the regional reference vowel space onto the speaker's vowel space as calculated from the accent identification data. Results for 58 speakers from the four regional accent areas are presented.

An Instrumental Study of Vowel Reduction and Stress Placement in Spanish-Accented English

Morphophonological alternations in English words such asableversusabilityinvolve changes in both stress and vowel quality. This study examined how native speakers of Spanish and English produced four such morphologically related English word pairs. Degree of stress and vowel quality was assessed auditorily and instrumentally. Stress placement generally seemed to constitute less of a learning problem for the native Spanish speakers than vowel reduction. The results suggest that Englishlike stress placement is acquired earlier than vowel reduction and that the ability to unstress vowels is a necessary, but not sufficient, condition for vowel reduction. The magnitude of stress and vowel quality differences for the four word pairs suggests that L2 learners acquire stress placement and vowel reduction in English on a word-by-word basis.

Measures of spectral tilt

Crude measures of spectral tilt (F0‐H2 difference, and F0‐F1 difference) have been demonstrated to be useful for distinguishing phonation types. However with such methods, it is difficult to control for differences due to variations in vowel quality and F0. In order to place such measures on a firmer foundation, the differences in vowel quality can be compensated for by inverse filtering. This technique has been used for analyzing vowels in languages having contrasting phonation types. FM recordings of airflow data in Burmese and Hmong, and ordinary AM audio recordings of !Xoo and Jalapa Mazatec were analyzed. AM recordings can be used, as phase distortion may be neglected while working in the frequency domain. FFT spectra were made of the inverse‐filtered waveforms. We considered several questions such as computational methods for deriving the amplitudes of harmonics, the expected dependency of amplitude on frequency, and the appropriate range of frequencies to examine. The results show that measures of spectral tilt obtained from inverse‐filtered data can be used to characterize differences in phonation type. [Work supported by NINCDS.]

Parameter interaction in the perception of French plosives.

This investigation takes as its point of departure observations on the production of French fortis versus lenis plosive consonants. In a series of perception tests the role of different parameters in the fortis versus lenis distinction found in production (e.g. duration of the pre-consonantal vowel, the consonantal closure, voicing during the closure and intensity of the consonantal release noise) was investigated. Apart from durational and intensity parameters, vowel quality differences (depending on the fortis versus lenis character of the following consonant) are also shown to play a part in phoneme identification. Furthermore it is shown that in obstruent clusters like /tp, dp/ versus /tg, dg/ not only do phonetic parameters like those mentioned above influence perception, but that also the phonemic identity of /p/ versus /g/ as fortis versus lenis contributes to the hearers' decision about the identity of the first consonant in the cluster. Phonetic as well as contextual factors are shown to interact in a complex manner. Implications of the results for speech perception theory are discussed.

Modeling the judgment of vowel quality differences.

The hypothesis of this study is that the auditory cues relevant to listeners' judgment of vowel quality are a spectral representation of loudness density versus pitch. A model is described that generates such patterns for steady-state vowels. In addition to the nonlinear transformations underlying the loudness density and pitch scales, it incorporates experimentally established characteristics associated with frequency resolution and masking, such as the critical band concept. This model is combined with a measure of auditory perceptual distance which, operating on pairs of vowels, treats each stimulus representation as a single spectral shape. In order to test the distance metric and the model, experimental data were gathered from listeners' numerical estimates of quality differences between stimulus pairs which compared four-formant and two-formant vowels. The correlation between experimental and theoretical results was 0.89. We interpret this value to indicate that the present definition of auditory cue and auditory distance can be said to account for the experimental behavior of our listeners only in a rather gross fashion. On the other hand, the theory was developed on the basis of rather conservative assumptions about the nature of auditory cues. For instance, the model ignores the possibility of temporal coding and certain nonlinear effects, and it does not pay special attention to spectral peaks. Seen in that light, the agreement between observed and predicted auditory distance is remarkably good.