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Vowel reduction in word-final position by early and late Spanish-English bilinguals

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ABSTRACT

Vowel reduction is a prominent feature of American English, as well as other stress-timed languages. As a phonological process, vowel reduction neutralizes multiple vowel quality contrasts in unstressed syllables. For bilinguals whose native language is not characterized by large spectral and durational differences between tonic and atonic vowels, systematically reducing unstressed vowels to the central vowel space can be problematic. Failure to maintain this pattern of stressed-unstressed syllables in American English is one key element that contributes to a “foreign accent” in second language speakers. Reduced vowels, or “schwas,” have also been identified as particularly vulnerable to the co-articulatory effects of adjacent consonants. The current study examined the effects of adjacent sounds on the spectral and temporal qualities of schwa in word-final position. Three groups of English-speaking adults were tested: Miami-based monolingual English speakers, early Spanish-English bilinguals, and late Spanish-English bilinguals. Subjects performed a reading task to examine their schwa productions in fluent speech when schwas were preceded by consonants from various points of articulation. Results indicated that monolingual English and late Spanish-English bilingual groups produced targeted vowel qualities for schwa, whereas early Spanish-English bilinguals lacked homogeneity in their vowel productions. This extends prior claims that schwa is targetless for F2 position for native speakers to highly-proficient bilingual speakers. Though spectral qualities lacked homogeneity for early Spanish-English bilinguals, early bilinguals produced schwas with near native-like vowel duration. In contrast, late bilinguals produced schwas with significantly longer durations than English monolinguals or early Spanish-English bilinguals. Our results suggest that the temporal properties of a language are better integrated into second language phonologies than spectral qualities. Finally, we examined the role of nonstructural variables (e.g. linguistic history measures) in predicting native-like vowel duration. These factors included: Age of L2 learning, amount of L1 use, and self-reported bilingual dominance. Our results suggested that different sociolinguistic factors predicted native-like reduced vowel duration than predicted native-like vowel qualities across multiple phonetic environments.

No MeSH data available.


Raw spectral values of schwa for all language groups.The x-axis shows F2 formants that correspond to a vowel’s position along the anterior-posterior dimension of the oral cavity. The y-axis shows F1 formants that correspond to vowel height.
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pone.0175226.g001: Raw spectral values of schwa for all language groups.The x-axis shows F2 formants that correspond to a vowel’s position along the anterior-posterior dimension of the oral cavity. The y-axis shows F1 formants that correspond to vowel height.

Mentions: Multivariate results indicated significant main effects for both independent variables “language group” (F (4, 1776) = 33.56, p <.001) and “preceding consonant” (F (6, 1776) = 10.83, p <.001). The interaction of language group * preceding consonant was not significant, p = .235. Results further indicated that a sizeable portion of the overall variance in vowel qualities that was present for variables F1, F2, and F2-F1 was explained by the predictors language group and preceding consonant (Adjusted R2 = .400). Language group and preceding consonant were also significant predictors for each of the spectral variables when considered individually, p <.001. Within groups, results indicated that schwas were systematically influenced by the phonetic features of the preceding consonant for at least one formant. Of the individual spectral variables, language group explained the highest percentage of variance for F1 (η2 = .11) with considerably less variance explained for F2 or F2-F1 (η2 = .03 for both DVs). In general, LBs produced higher F1 values than either EMs or EBs, indicating a lower vowel position. EMs demonstrated the most homogenous spectral qualities for word-final schwa, while EBs differed markedly in their F2 values (Fig 1).


Vowel reduction in word-final position by early and late Spanish-English bilinguals
Raw spectral values of schwa for all language groups.The x-axis shows F2 formants that correspond to a vowel’s position along the anterior-posterior dimension of the oral cavity. The y-axis shows F1 formants that correspond to vowel height.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383264&req=5

pone.0175226.g001: Raw spectral values of schwa for all language groups.The x-axis shows F2 formants that correspond to a vowel’s position along the anterior-posterior dimension of the oral cavity. The y-axis shows F1 formants that correspond to vowel height.
Mentions: Multivariate results indicated significant main effects for both independent variables “language group” (F (4, 1776) = 33.56, p <.001) and “preceding consonant” (F (6, 1776) = 10.83, p <.001). The interaction of language group * preceding consonant was not significant, p = .235. Results further indicated that a sizeable portion of the overall variance in vowel qualities that was present for variables F1, F2, and F2-F1 was explained by the predictors language group and preceding consonant (Adjusted R2 = .400). Language group and preceding consonant were also significant predictors for each of the spectral variables when considered individually, p <.001. Within groups, results indicated that schwas were systematically influenced by the phonetic features of the preceding consonant for at least one formant. Of the individual spectral variables, language group explained the highest percentage of variance for F1 (η2 = .11) with considerably less variance explained for F2 or F2-F1 (η2 = .03 for both DVs). In general, LBs produced higher F1 values than either EMs or EBs, indicating a lower vowel position. EMs demonstrated the most homogenous spectral qualities for word-final schwa, while EBs differed markedly in their F2 values (Fig 1).

View Article: PubMed Central - PubMed

ABSTRACT

Vowel reduction is a prominent feature of American English, as well as other stress-timed languages. As a phonological process, vowel reduction neutralizes multiple vowel quality contrasts in unstressed syllables. For bilinguals whose native language is not characterized by large spectral and durational differences between tonic and atonic vowels, systematically reducing unstressed vowels to the central vowel space can be problematic. Failure to maintain this pattern of stressed-unstressed syllables in American English is one key element that contributes to a &ldquo;foreign accent&rdquo; in second language speakers. Reduced vowels, or &ldquo;schwas,&rdquo; have also been identified as particularly vulnerable to the co-articulatory effects of adjacent consonants. The current study examined the effects of adjacent sounds on the spectral and temporal qualities of schwa in word-final position. Three groups of English-speaking adults were tested: Miami-based monolingual English speakers, early Spanish-English bilinguals, and late Spanish-English bilinguals. Subjects performed a reading task to examine their schwa productions in fluent speech when schwas were preceded by consonants from various points of articulation. Results indicated that monolingual English and late Spanish-English bilingual groups produced targeted vowel qualities for schwa, whereas early Spanish-English bilinguals lacked homogeneity in their vowel productions. This extends prior claims that schwa is targetless for F2 position for native speakers to highly-proficient bilingual speakers. Though spectral qualities lacked homogeneity for early Spanish-English bilinguals, early bilinguals produced schwas with near native-like vowel duration. In contrast, late bilinguals produced schwas with significantly longer durations than English monolinguals or early Spanish-English bilinguals. Our results suggest that the temporal properties of a language are better integrated into second language phonologies than spectral qualities. Finally, we examined the role of nonstructural variables (e.g. linguistic history measures) in predicting native-like vowel duration. These factors included: Age of L2 learning, amount of L1 use, and self-reported bilingual dominance. Our results suggested that different sociolinguistic factors predicted native-like reduced vowel duration than predicted native-like vowel qualities across multiple phonetic environments.

No MeSH data available.