Children's perception of conversational and clear American-English vowels in noise

Purpose: Much of a child’s day is spent listening to speech in the presence of background noise. Although accurate vowel perception is important for listeners’ accurate speech perception and comprehension, little is known about children’s vowel perception in noise. “Clear speech” is a speech style frequently used by talkers in the presence of noise. This study investigated children’s identification of vowels in nonsense words in noise and examined whether adults’ use of clear speech would result in the children’s more accurate vowel identification. Method: Two female American-English (AE) speaking adults were recorded producing the nonsense word /gəbVpə/ with AE vowels /ɛ-æ-ɑ-ʌ/ in phrases in conversational and clear speech. These utterances were presented to 15 AE-speaking children (ages 5.0-8.5) at a signal-to-noise ratio of -6 dB. The children repeated the utterances. Results: Clear speech vowels were repeated significantly more accurately (87%) than conversational speech vowels (59%), suggesting that clear speech aids children’s vowel identification. Children repeated one talker’s vowels more accurately than the other’s, and front vowels more accurately than central and back vowels. Conclusions: The findings support the use of clear speech for enhancing adult-to-child communication in AE in noisy environments

Perception of French Vowels by American English Adults With and Without French Language Experience

This study investigated the effects of language experience and consonantal context on American English (AE) listeners’ discrimination of contrasts involving Parisian French vowels /y, œ, u, i/. Vowels were produced in /rabVp/ and /rabVt/ nonsense disyllables in carrier phrases by 3 speakers and presented in a categorial AXB discrimination task. Two groups were tested: AE listeners who had studied French extensively beginning after age 13 (Exp) and non-French-speaking AE listeners (Inexp). The Exp group performed better than the Inexp group on /u-œ/, /i-y/ and /y-œ/ (mean errors: Exp=5%, Inexp=24%). However, for /u-y/, the groups did not differ (Exp=30% vs Inexp=24% errors). The Inexp group confused /i-y/ more often in bilabial context, but /u-y/ more often in alveolar context, whereas the Exp group confused /u-y/ in both contexts. Overall, the Inexp group performed better in bilabial than in alveolar context (16% vs 32% errors), whereas the Exp group revealed no context effect. Results suggest that learning a second language (L2) includes learning its coarticulatory rules. Implications for models of L2-speech perception are discussed

The Effects of Two Speech Interventions on Speech Function in Pediatric Dysarthria

Reduced speech function is a primary disability in children with cerebral palsy (CP) who have the motor speech disorder of dysarthria. Interventions for pediatric dysarthria with evidence of efficacy are greatly needed. The present exploratory study examined the effects of two intervention methods on three children with CP: (1) Lee Silverman Voice Treatment (LSVT LOUD), an intensive single-focus intervention protocol that increases sound pressure level (SPL), intelligibility, and vowel space in adults with dysarthria due to Parkinson Disease (PD) and has recent evidence suggesting effectiveness for children with CP, and (2) “Traditional” intervention, representing “treatment as usual,” consisting of instruction on breath control, positioning, articulation, and other behaviors. Examination of caregiver questionnaires, articulation assessment, and blinded listener ratings revealed greater speech function and articulatory precision, as well as utterances more often preferred and perceived as “easier to understand” after intervention. LSVT LOUD resulted in increases in speech function and SPL. Traditional resulted in increased speech function without increasing SPL. Thus, both interventions show promise for yielding increased speech function in children with dysarthria, although success may vary across linguistic levels and children

Perception of American–English Vowels by Early and Late Spanish–English Bilinguals

Increasing numbers of Hispanic immigrants are entering the US and learning American–English (AE) as a second language (L2). Previous studies investigating the relationship between AE and Spanish vowels have revealed an advantage for early L2 learners for their accuracy of L2 vowel perception. Replicating and extending such previous research, this study examined the patterns with which early and late Spanish–English bilingual adults assimilated naturally-produced AE vowels to their native vowel inventory and the accuracy with which they discriminated the vowels. Twelve early Spanish–English bilingual, 12 late Spanish–English bilingual, and 10 monolingual listeners performed perceptual-assimilation and categorical-discrimination tasks involving AE /i,ɪ,ɛ,ʌ,æ,ɑ,o/. Early bilinguals demonstrated similar assimilation patterns to late bilinguals. Late bilinguals’ discrimination was less accurate than early bilinguals’ and AE monolinguals’. Certain contrasts, such as /æ-ɑ/, /ʌ-ɑ/, and /ʌ-æ/, were particularly difficult to discriminate for both bilingual groups. Consistent with previous research, findings suggest that early L2 learning heightens Spanish–English bilinguals’ ability to perceive cross-language phonetic differences. However, even early bilinguals’ native-vowel system continues to influence their L2 perception

Neurophysiological indices of the effect of cognates on vowel perception in late Spanish-English bilinguals

It is well established that acquiring a second language (L2) later in life results in less accurate production and perception of speech sounds in the L2. Languages like Spanish and English have many common words (cognates) and similar sounds, learning how the combination of cognate status and sound similarity can affect processing and lexical access in an L2 is of interest to educators. In the present study, fifteen monolingual English-speakers and 15 late Spanish-English bilinguals were presented with Spanish-English cognates and non-cognates. Event related potentials (ERP) were used to determine whether late L2-learners had more difficulty discriminating mispronunciations of vowels in English words that have Spanish cognates compared to words that do not have cognates. Behavioral results indicated effects of language background differences, but not cognate status, on participants’ ability to discriminate mispronunciations of English vowels, with bilinguals showing poorer discrimination. ERP results revealed that cognate words facilitated L2 phonological processing as evidenced by a larger frontal positive component (P400) ERP effect, similar in amplitude to the P400 from monolinguals. Results suggest that cognate words facilitate not only vocabulary acquisition, but also speech processing, in adult L2 learners, and, thus, may also be useful as a tool for perceptual learning

Speech Treatment Effects on Narrative Intelligibility in French-Speaking Children with Dysarthria.

Purpose: This study examined the effects of Speech Intelligibility Treatment (SIT) on intelligibility and naturalness of narrative speech produced by francophone children with dysarthria due to cerebral palsy (CP). Method: Ten francophone children with dysarthria were randomized to one of two treatments, Speech Intelligibility Treatment or Hand-arm Bimanual Intensive Therapy Including Lower Extremities, a physical therapy (PT) treatment. Both treatments were conducted in a camp setting and were comparable in dosage. The children were recorded pre- and post-treatment producing a story narrative. Intelligibility was measured by means of 60 blinded listeners’ orthographic transcription accuracy (percentage of words transcribed correctly). The listeners also rated the children’s naturalness on a visual analogue scale. Results: A significant pre- to post-treatment increase in intelligibility was found for the SIT group, but not for the PT group, with great individual variability observed among the children. No significant changes were found for naturalness ratings or sound pressure level in the SIT group or the PT group post-treatment. Articulation rate increased in both treatment groups, although not differentially across treatments. Conclusion: Findings from this first treatment study on intelligibility in francophone children with dysarthria suggest that SIT shows promise for increasing narrative intelligibility in this population. Acoustic contributors to the increased intelligibility remain to be explored further

Acoustic and perceptual consequences of speech cues for children with dysarthria

Purpose: Reductions in articulatory working space and vocal intensity have been linked to intelligibility deficits in children with dysarthria due to cerebral palsy. However, few studies have examined the outcomes of behavioral treatments aimed at these underlying impairments or investigated which treatment cues might best facilitate improved intelligibility. This study assessed the effects of cues targeting clear speech (i.e., “Speak with your big mouth”) and greater vocal intensity (i.e., “Speak with your strong voice”) on acoustic measures of speech production and intelligibility. Method: Eight children with spastic dysarthria due to cerebral palsy repeated sentence- and word-level stimuli across habitual, big mouth, and strong voice conditions. Acoustic analyses were conducted, and 48 listeners completed orthographic transcription and scaled intelligibility ratings. Results: Both cues resulted in significant changes to vocal intensity and speech rate although the degree of change varied by condition. In a similar manner, perceptual analysis revealed significant improvements to intelligibility with both cues; however, at the single-word level, big mouth outperformed strong voice. Conclusion: Children with dysarthria are capable of changing their speech styles differentially in response to cueing. Both the big mouth and strong voice cues hold promise as intervention strategies to improve intelligibility in this population. Supplemental Material: https://doi.org/10.23641/asha.511684

Perceptual and acoustic effects of dual-focus speech treatment in children with dysarthria

Purpose: Children with dysarthria secondary to cerebral palsy (CP) may experience reduced speech intelligibility and diminished communicative participation. However, minimal research has been conducted examining the outcomes of behavioral speech treatments in this population. This study examined the effect of Speech Intelligibility Treatment (SIT), a dual-focus speech treatment targeting increased articulatory excursion and vocal intensity, on intelligibility of narrative speech, speech acoustics, and communicative participation in children with dysarthria. Method: American-English speaking children with dysarthria (n = 17) received SIT in a three-week summer camp-like setting at Columbia University. SIT follows motor-learning principles to train the child-friendly, dual-focus strategy, “Speak with your big mouth and strong voice.” Children produced a story narrative at baseline (BASE), immediate post-treatment (POST), and at 6-week follow-up (FUP). Outcomes were examined via blinded listener ratings of ease of understanding (n = 108 adult listeners), acoustic analyses, and questionnaires focused on communicative participation. Results: SIT resulted in significant increases in ease of understanding at POST, that were maintained at FUP. There were no significant changes to vocal intensity, speech rate, or vowel spectral characteristics, with the exception of an increase in second formant difference between vowels following SIT. Significantly enhanced communicative participation was evident at POST and FUP. Considerable variability in response to SIT was observed between children. Conclusion: Dual-focus treatment shows promise for improving intelligibility and communicative participation in children with dysarthria, although responses to treatment vary considerably across children. Possible mechanisms underlying the intelligibility gains, enhanced communicative participation, and variability in treatment effects are discussed

Perception of American English Consonants /v/ and /w/ by Hindi Speakers of English

This study examined perception of the American English (AE) /v/-/w/ consonant contrast by Hindi speakers of English as a second language (L2). A second aim was to determine whether residence in the US modulated perception of this difficult contrast for proficient bilingual Hindi-English listeners. Two groups of Hindi-English bilinguals (the first resided in the US for more than five years, the second lived in India) and a group of AE-speaking listeners participated in the study. Listeners’ identification and discrimination of nonsense words (e.g., “vagag” vs. “wagag”) were examined. Hindi listeners performed significantly less accurately than AE controls. Accuracy by Hindi listeners was near chance for identification and higher-than-chance for discrimination. Exposure to AE in the US did not improve performance. These results are consistent with previous studies of late L2 learners and extend findings to a population that was proficient in an L2 before arriving in the L2 environment

The effects of intensive speech treatment on conversational intelligibility in Spanish speakers with Parkinson’s disease

Purpose: To examine the effects of intensive speech treatment on the conversational intelligibility of Castilian Spanish speakers with Parkinson’s disease (PD), as well as on the speakers’ self-perceptions of disability. Method: Fifteen speakers with a medical diagnosis of PD participated in this study. Speech recordings were completed twice before treatment, immediately post-treatment and at a one-month follow-up session. Conversational intelligibility was assessed in two ways—transcription accuracy scores and intelligibility ratings on a 9-point Likert scale. The Voice Handicap Index (VHI) was administered as a measure of self-perceived disability. Results: Group data revealed that transcription accuracy and median ease-of-understanding ratings increased significantly immediately post-treatment, with gains maintained at the one-month follow-up. The functional subscale of the VHI decreased significantly post-treatment, suggesting a decrease in perceived communication disability after speech treatment. Conclusion: These findings support the implementation of intensive voice treatment to improve conversational intelligibility in Spanish speakers with PD with dysarthria as well as to improve the speakers' perception of their daily communicative capabilities. Clinical and theoretical considerations are discussed