Enhanced contrast for vowels in utterance focus: a cross-language study

The Acoustics of Gender in Indian English: Toward Forensic Profiling in a Multilingual Context

The present study is an acoustic analysis of Indian English, specifically examining the speech patterns and characteristics of three different groups with different native languages. This study investigates fundamental frequency (fo), fo range, fo variance, formant frequencies, and vowel space size in 42 native male and female speakers of Odia, Bangla, and Hindi. Furthermore, it investigated the potential correlation between fundamental frequency and vowel space, examining whether variations in vowel space size could be influenced by gender-specific perceptual factors. The paper emphasizes that in a multilingual context, gender identification can be efficiently correlated with both fo and formant frequencies. To measure a range of acoustic characteristics, speech samples were collected from the recording task. Analysis was done on PRAAT. The study revealed significant differences between genders for the examined acoustic characteristics. Results indicate differences in the size of gender-specific variations among the language groups, with females exhibiting more significant differences in fo, formant frequencies, and vowel space than males. The findings show no significant correlation between fo and vowel space area, indicating that other features are responsible for large vowel space for females. These findings display significant potential toward creating a robust empirical framework for gender profiling that can be utilized in a wide range of forensic linguistics investigations.

Identification and Comprehension of Narrow Focus by Arabic-Speaking Adolescents With Moderate-to-Profound Hearing Loss

PURPOSE

Processing narrow focus (NF), the stressed word in the sentence, includes both the perceptual ability to identify the stressed word in the sentence and the pragmatic-semantic ability to comprehend the nonexplicit linguistic message. NF and its underlying meaning can be conveyed only via the auditory modality. Therefore, NF can be considered as a measure for assessing the efficacy of the hearing aid (HA) and cochlear implants (CIs) for acquiring nonexplicit language skills. The purpose of this study was to assess identification and comprehension of NF by HA and CI users who are native speakers of Arabic and to associate NF outcomes with speech perception and cognitive and linguistic abilities.

METHOD

A total of 46 adolescents (age range: 11;2-18;8) participated: 18 with moderate-to-severe hearing loss who used HAs, 10 with severe-to-profound hearing loss who used CIs, and 18 with typical hearing (TH). Test materials included the Arabic Narrow Focus Test (ANFT), which includes three subtests assessing identification (ANFT1), comprehension of NF in simple four-word sentences (ANFT2), and longer sentences with a construction list at the clause or noun phrase level (ANFT3). In addition, speech perception, vocabulary, and working memory were assessed.

RESULTS

All the participants successfully identified the word carrying NF, with no significant difference between the groups. Comprehension of NF in ANFT2 and ANFT3 was reduced for HA and CI users compared with TH peers, and speech perception, hearing status, and memory for digits predicted the variability in the overall results of ANFT1, ANFT2, and ANFT3, respectively.

CONCLUSIONS

Arabic speakers who used HAs or CIs were able to identify NF successfully, suggesting that the acoustic cues were perceptually available to them. However, HA and CI users had considerable difficulty in understanding NF. Different factors may contribute to this difficulty, including the memory load during the task as well as pragmatic-linguistic knowledge on the possible meanings of NF.

Examining vocal attractiveness through articulatory working space

Robust gender differences exist in the acoustic correlates of clearly articulated speech, with females, on average, producing speech that is acoustically and phonetically more distinct than that of males. This study investigates the relationship between several acoustic correlates of clear speech and subjective ratings of vocal attractiveness. Talkers were recorded producing vowels in /bVd/ context and sentences containing the four corner vowels. Multiple measures of working vowel space were computed from continuously sampled formant trajectories and were combined with measures of speech timing known to co-vary with clear articulation. Partial least squares regression (PLS-R) modeling was used to predict ratings of vocal attractiveness for male and female talkers based on the acoustic measures. PLS components that loaded on size and shape measures of working vowel space-including the quadrilateral vowel space area, convex hull area, and bivariate spread of formants-along with measures of speech timing were highly successful at predicting attractiveness in female talkers producing /bVd/ words. These findings are consistent with a number of hypotheses regarding human attractiveness judgments, including the role of sexual dimorphism in mate selection, the significance of traits signalling underlying health, and perceptual fluency accounts of preferences.

The Processing of Linguistic Prominence

Prominence, the expression of informational weight within utterances, can be signaled by prosodic highlighting (head-prominence, as in English) or by position (as in Korean edge-prominence). Prominence confers processing advantages, even if conveyed only by discourse manipulations. Here we compared processing of prominence in English and Korean, using a task that indexes processing success, namely recognition memory. In each language, participants' memory was tested for target words heard in sentences in which they were prominent due to prosody, position, both or neither. Prominence produced recall advantage, but the relative effects differed across language. For Korean listeners the positional advantage was greater, but for English listeners prosodic and syntactic prominence had equivalent and additive effects. In a further experiment semantic and phonological foils tested depth of processing of the recall targets. Both foil types were correctly rejected, suggesting that semantic processing had not reached the level at which word form was no longer available. Together the results suggest that prominence processing is primarily driven by universal effects of information structure; but language-specific differences in frequency of experience prompt different relative advantages of prominence signal types. Processing efficiency increases in each case, however, creating more accurate and more rapidly contactable memory representations.

Phonetic Implementation of Prosodic Emphasis in Preschool-Aged Children and Adults: Probing the Development of Sensorimotor Speech Goals

Objective We aimed to investigate the production of contrastive emphasis in French-speaking 4-year-olds and adults. Based on previous work, we predicted that, due to their immature motor control abilities, preschool-aged children would produce smaller articulatory differences between emphasized and neutral syllables than adults. Method Ten 4-year-old children and 10 adult French speakers were recorded while repeating /bib/, /bub/, and /bab/ sequences in neutral and contrastive emphasis conditions. Synchronous recordings of tongue movements, lip and jaw positions, and speech signals were made. Lip positions and tongue shapes were analyzed; formant frequencies, amplitude, fundamental frequency, and duration were extracted from the acoustic signals; and between-vowel contrasts were calculated. Results Emphasized vowels were higher in pitch, intensity, and duration than their neutral counterparts in all participants. However, the effect of contrastive emphasis on lip position was smaller in children. Prosody did not affect tongue position in children, whereas it did in adults. As a result, children's productions were perceived less accurately than those of adults. Conclusion These findings suggest that 4-year-old children have not yet learned to produce hypoarticulated forms of phonemic goals to allow them to successfully contrast syllables and enhance prosodic saliency.

The Impact of Contrastive Stress on Vowel Acoustics and Intelligibility in Dysarthria

PURPOSE

To compare vowel acoustics and intelligibility in words produced with and without contrastive stress by speakers with spastic (mixed-spastic) dysarthria secondary to cerebral palsy (DYSCP) and healthy controls (HCs).

METHOD

Fifteen participants (9 men, 6 women; age M = 42 years) with DYSCP and 15 HCs (9 men, 6 women; age M = 36 years) produced sentences containing target words with and without contrastive stress. Forty-five healthy listeners (age M = 25 years) completed a vowel identification task of DYSCP productions. Vowel acoustics were compared across stress conditions and groups using 1st (F1) and 2nd (F2) formant measures. Perceptual intelligibility was compared across stress conditions and dysarthria severity.

RESULTS

F1 and F2 significantly increased in stressed words for both groups, although the degree of change differed. Mean Euclidian distance between vowels also increased with stress. The relative probability of vowels falling within the target F1 × F2 space was greater for HCs but did not differ with stress. Stress production resulted in greater listener vowel identification accuracy for speakers with mild dysarthria.

CONCLUSIONS

Contrastive stress affected vowel formants for both groups. Perceptual results suggest that some speakers with dysarthria may benefit from a contrastive stress strategy to improve vowel intelligibility.

Speaking Clearly for the Blind: Acoustic and Articulatory Correlates of Speaking Conditions in Sighted and Congenitally Blind Speakers

Compared to conversational speech, clear speech is produced with longer vowel duration, greater intensity, increased contrasts between vowel categories, and decreased dispersion within vowel categories. Those acoustic correlates are produced by larger movements of the orofacial articulators, including visible (lips) and invisible (tongue) articulators. Thus, clear speech provides the listener with audible and visual cues that are used to increase the overall intelligibility of speech produced by the speaker. It is unclear how those cues are produced by visually impaired speakers who never had access to vision. In this paper, we investigate the acoustic and articulatory correlates of vowels in clear versus conversational speech, and in sighted and congenitally blind speakers. Participants were recorded using electroarticulography while producing multiple repetitions of the ten Quebec French oral vowels in carrier sentences in both speaking conditions. Articulatory variables (lip, jaw, and tongue positions) as well as acoustic variables (contrasts between vowels, within-vowel dispersion, pitch, duration, and intensity) were measured. Lip movements were larger when going from conversational to clear speech in sighted speakers only. On the other hand, tongue movements were affected to a larger extent in blind speakers compared to their sighted peers. These findings confirm that vision plays an important role in the maintenance of speech intelligibility.

Articulatory and acoustic correlates of contrastive focus in congenitally blind adults and sighted adults

PURPOSE

The role of vision in speech representation was investigated in congenitally blind speakers and sighted speakers by studying the correlates of contrastive focus, a prosodic condition in which phonemic contrasts are enhanced. It has been reported that the lips (visible articulators) are less involved in implementing the rounding feature for blind speakers. If the weight of visible gestures in speech representation is reduced in blind speakers, they should show different strategies to mark focus-induced prominence.

METHOD

Nine congenitally blind French speakers and 9 sighted French speakers were recorded while uttering sentences in neutral and contrastive focus conditions. Internal lip area, upper lip protrusion, and acoustic values (formants, fundamental frequency, duration, and intensity) were measured.

RESULTS

In the acoustic domain, both groups signaled focus by using comparable values of fundamental frequency, intensity, and duration. Formant values in sighted speakers were more affected by the prosodic condition. In the articulatory domain, sighted speakers significantly altered lip geometry in the contrastive focus condition compared with the neutral condition, whereas blind speakers did not.

CONCLUSION

These results suggest that implementation of prosodic focus is affected by congenital visual deprivation. The authors discuss how these findings can be interpreted in the framework of the perception-for-action-control theory.

The development of distinct speaking styles in preschool children

PURPOSE

To examine when and how socially conditioned distinct speaking styles emerge in typically developing preschool children's speech.

METHOD

Thirty preschool children, ages 3, 4, and 5 years old, produced target monosyllabic words with monophthongal vowels in different social-functional contexts designed to elicit clear and casual speaking styles. Thirty adult listeners were used to assess whether and at what age style differences were perceptible. Children's speech was acoustically analyzed to evaluate how style-dependent differences were produced.

RESULTS

The ratings indicated that listeners could not discern style differences in 3-year-olds' speech but could hear distinct styles in 4-year-olds' and especially in 5-year-olds' speech. The acoustic measurements were consistent with these results: Style-dependent differences in 4- and 5-year-olds' words included shorter vowel durations and lower fundamental frequency in clear compared with casual speech words. Five-year-olds' clear speech words also had more final stop releases and initial sibilants with higher spectral energy than did their casual speech words. Formant frequency measures showed no style-dependent differences in vowel production at any age nor any differences in initial stop voice onset times.

CONCLUSION

Overall, the findings suggest that distinct styles develop slowly and that early style-dependent differences in children's speech are unlike those observed in adult clear and casual speech. Children may not develop adultlike styles until they have acquired expert articulatory control and the ability to highlight the internal structure of an articulatory plan for a listener.

Acoustic and auditory phonetics: the adaptive design of speech sound systems

Speech perception is remarkably robust. This paper examines how acoustic and auditory properties of vowels and consonants help to ensure intelligibility. First, the source-filter theory of speech production is briefly described, and the relationship between vocal-tract properties and formant patterns is demonstrated for some commonly occurring vowels. Next, two accounts of the structure of preferred sound inventories, quantal theory and dispersion theory, are described and some of their limitations are noted. Finally, it is suggested that certain aspects of quantal and dispersion theories can be unified in a principled way so as to achieve reasonable predictive accuracy.

Stability of Temporal Contrasts across Speaking Styles in English and Croatian

In this paper we investigate the effect of clear speech, a distinct, listener-oriented, intelligibility-enhancing mode of speech production, on vowel and stop consonant contrasts along the temporal dimension in English and Croatian. Our previous work has shown that, in addition to enhancing the overall acoustic salience of the speech signal through a decrease in speaking rate and expansion of pitch range, clear speech modifications increased the spectral distances between vowel categories in both languages despite the different sizes of their vowel inventories (+10 in English, 5 in Croatian). Here, we examine how clear speech affects the duration of English tense ('long') vs. lax ('short') vowels, English vowels preceding voiced ('long') vs. voiceless ('short') coda stops, Croatian long vs. short vowels and Croatian and English VOT duration for voiced and voiceless stops. Overall, the results showed that the proportional distance between the 'short' and 'long' vowel categories and between the voiced and voiceless stop categories was remarkably stable across the two speaking styles in both languages. These results suggest that, in combination with the spectral enhancement of vowel contrasts, language-specific pronunciation norms along the temporal dimension are maintained in clear and conversational speech.

Training Japanese listeners to perceive American English vowels: influence of training sets

PURPOSE

Studies on speech perception training have shown that adult 2nd language learners can learn to perceive non-native consonant contrasts through laboratory training. However, research on perception training for non-native vowels is still scarce, and none of the previous vowel studies trained more than 5 vowels. In the present study, the influence of training set sizes was investigated by training native Japanese listeners to identify American English (AE) vowels.

METHOD

Twelve Japanese learners of English were trained 9 days either on 9 AE monophthongs (fullset training group) or on the 3 more difficult vowels (subset training group). Five listeners served as controls and received no training. Performance of listeners was assessed before and after training as well as 3 months after training was completed.

RESULTS

Results indicated that (a) fullset training using 9 vowels in the stimulus set improved average identification by 25%; (b) listeners in both training groups generalized improvement to untrained words and tokens spoken by novel speakers; and (c) both groups maintained improvement after 3 months. However, the subset group never improved on untrained vowels.

CONCLUSIONS

Training protocols for learning non-native vowels should present a full set of vowels and should not focus only on the more difficult vowels.

Acoustic variability within and across German, French, and American English vowels: phonetic context effects

Cross-language perception studies report influences of speech style and consonantal context on perceived similarity and discrimination of non-native vowels by inexperienced and experienced listeners. Detailed acoustic comparisons of distributions of vowels produced by native speakers of North German (NG), Parisian French (PF) and New York English (AE) in citation (di)syllables and in sentences (surrounded by labial and alveolar stops) are reported here. Results of within- and cross-language discriminant analyses reveal striking dissimilarities across languages in the spectral/temporal variation of coarticulated vowels. As expected, vocalic duration was most important in differentiating NG vowels; it did not contribute to PF vowel classification. Spectrally, NG long vowels showed little coarticulatory change, but back/low short vowels were fronted/raised in alveolar context. PF vowels showed greater coarticulatory effects overall; back and front rounded vowels were fronted, low and mid-low vowels were raised in both sentence contexts. AE mid to high back vowels were extremely fronted in alveolar contexts, with little change in mid-low and low long vowels. Cross-language discriminant analyses revealed varying patterns of spectral (dis)similarity across speech styles and consonantal contexts that could, in part, account for AE listeners' perception of German and French front rounded vowels, and "similar" mid-high to mid-low vowels.