How much does language proficiency by non-native listeners influence speech audiometric tests in noise?

Intelligibility of Natively and Nonnatively Produced English Speech Presented in Noise to a Large Cohort of United States Service Members

PURPOSE

A corpus of English matrix sentences produced by 60 native and nonnative speakers of English was developed as part of a multinational coalition task group. This corpus was tested on a large cohort of U.S. Service members in order to examine the effects of talker nativeness, listener nativeness, masker type, and hearing sensitivity on speech recognition performance in this population.

METHOD

A total of 1,939 U.S. Service members (ages 18-68 years) completed this closed-set listening task, including 430 women and 110 nonnative English speakers. Stimuli were produced by native and nonnative speakers of English and were presented in speech-shaped noise and multitalker babble. Keyword recognition accuracy and response times were analyzed.

RESULTS

General(ized) linear mixed-effects regression models found that, on the whole, speech recognition performance was lower for listeners who identified as nonnative speakers of English and when listening to speech produced by nonnative speakers of English. Talker and listener effects were more pronounced when listening in a babble masker than in a speech-shaped noise masker. Response times varied as a function of recognition score, with longest response times found for intermediate levels of performance.

CONCLUSIONS

This study found additive effects of talker and listener nonnativeness when listening to speech in background noise. These effects were present in both accuracy and response time measures. No multiplicative effects of talker and listener language background were found. There was little evidence of a negative interaction between talker nonnativeness and hearing impairment, suggesting that these factors may have redundant effects on speech recognition.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26060191.

Age Impacts Speech-in-Noise Recognition Differently for Nonnative and Native Listeners

PURPOSE

The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age.

METHOD

Retrospective analyses were performed on three large data sets containing suprathreshold auditory tests completed by 5,572 participants who were self-identified native and nonnative speakers of English between the ages of 18-65 years, including a binaural tone detection test, a digit identification test, and a sentence recognition test.

RESULTS

The analyses show a significant interaction between increasing age and participant group on tests involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection test. For both speech tests, differences in speech recognition emerged between groups during early adulthood, and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants.

CONCLUSIONS

This set of analyses extends the existing literature by examining interactions between aging and self-identified native English speaker status in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater-than-expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Online Assessment of Speech Perception and Auditory Spectrotemporal Processing in Spanish-English Bilinguals

PURPOSE

There is limited access to audiology services for the growing population of Spanish-English bilinguals in the United States. Online auditory testing can potentially provide a cost-effective alternative to in-person visits. However, even for bilinguals with high English proficiency, age of English acquisition may affect speech perception accuracy. This study used a comprehensive test battery to assess speech perception and spectrotemporal processing abilities in Spanish-English bilinguals and to evaluate susceptibility of different tests to effects of native language.

METHOD

The online battery comprised three tests of speech in quiet (vowel and consonant identification and words in sentences), four tests of speech perception in noise (two for intelligibility and two for comprehension), and three tests of spectrotemporal processing (two tests of stochastically modulated pattern discrimination and one test of spectral resolution). Participants were 28 adult Spanish-English bilinguals whose English acquisition began either early (≤ 6 years old) or late (≥ 7 years old) and 18 English monolingual speakers.

RESULTS

Significant differences were found in six of the 10 tests. The differences were most pronounced for vowel perception in quiet, speech-in-noise test, and two tests of speech comprehension in noise. Late bilinguals consistently scored lower than native English speakers or early bilinguals. In contrast, no differences between groups were observed for digits-in-noise or three tests of spectrotemporal processing abilities.

CONCLUSION

The findings suggest initial feasibility of online assessment in this population and can inform selection of tests for auditory assessment of Spanish-English bilinguals.

Bilinguals' speech perception in noise: Perceptual and neural associations

The current study characterized subcortical speech sound processing among monolinguals and bilinguals in quiet and challenging listening conditions and examined the relation between subcortical neural processing and perceptual performance. A total of 59 normal-hearing adults, ages 19–35 years, participated in the study: 29 native Hebrew-speaking monolinguals and 30 Arabic-Hebrew-speaking bilinguals. Auditory brainstem responses to speech sounds were collected in a quiet condition and with background noise. The perception of words and sentences in quiet and background noise conditions was also examined to assess perceptual performance and to evaluate the perceptual-physiological relationship. Perceptual performance was tested among bilinguals in both languages (first language (L1-Arabic) and second language (L2-Hebrew)). The outcomes were similar between monolingual and bilingual groups in quiet. Noise, as expected, resulted in deterioration in perceptual and neural responses, which was reflected in lower accuracy in perceptual tasks compared to quiet, and in more prolonged latencies and diminished neural responses. However, a mixed picture was observed among bilinguals in perceptual and physiological outcomes in noise. In the perceptual measures, bilinguals were significantly less accurate than their monolingual counterparts. However, in neural responses, bilinguals demonstrated earlier peak latencies compared to monolinguals. Our results also showed that perceptual performance in noise was related to subcortical resilience to the disruption caused by background noise. Specifically, in noise, increased brainstem resistance (i.e., fewer changes in the fundamental frequency (F0) representations or fewer shifts in the neural timing) was related to better speech perception among bilinguals. Better perception in L1 in noise was correlated with fewer changes in F0 representations, and more accurate perception in L2 was related to minor shifts in auditory neural timing. This study delves into the importance of using neural brainstem responses to speech sounds to differentiate individuals with different language histories and to explain inter-subject variability in bilinguals’ perceptual abilities in daily life situations.

Vocal and semantic cues for the segregation of long concurrent speech stimuli in diotic and dichotic listening-The Long-SWoRD test

It is not always easy to follow a conversation in a noisy environment. To distinguish between two speakers, a listener must mobilize many perceptual and cognitive processes to maintain attention on a target voice and avoid shifting attention to the background noise. The development of an intelligibility task with long stimuli-the Long-SWoRD test-is introduced. This protocol allows participants to fully benefit from the cognitive resources, such as semantic knowledge, to separate two talkers in a realistic listening environment. Moreover, this task also provides the experimenters with a means to infer fluctuations in auditory selective attention. Two experiments document the performance of normal-hearing listeners in situations where the perceptual separability of the competing voices ranges from easy to hard using a combination of voice and binaural cues. The results show a strong effect of voice differences when the voices are presented diotically. In addition, analyzing the influence of the semantic context on the pattern of responses indicates that the semantic information induces a response bias in situations where the competing voices are distinguishable and indistinguishable from one another.

Effects of language experience on selective auditory attention and speech-in-noise perception among English second language learners: Preliminary findings

OBJECTIVE

The purpose of the study was to examine the effects of language experience on selective auditory attention and speech-in-noise perception in English Second Language (ESL) learners aged seven to eight years.

METHOD

A quantitative, descriptive, comparative cross-sectional research design was used to determine the effect of age of exposure to English on the selective auditory attention abilities and speech-in-noise perception skills of 40 children with normal hearing in first or second grade (aged seven to eight years). The control group comprised of 20 English first language (EFL) learners (mean age = 7.35 years ±0.49) and the research group included 20 s language learners (mean age = 7.70 years ±0.47). In order to compare the control and research groups with respect to the age of exposure to English through various sources, the Mann Whitney test was used. Information regarding the age of exposure was gathered by a case history questionnaire, completed by the parents/guardians of the participants. The Selective Auditory Attention Test (SAAT) and Digits-in-Noise (DIN) test were performed in one sitting.

RESULTS

No statistically significant differences between the EFL and ESL groups were found for the SAAT and DIN. However, a statistically significant difference was obtained between the SAAT lists 1 and 3 & the DIN: diotic listening condition for the ESL group only (r_s = -0.623; p = 0.003). The difference between the EFL and ESL groups in the mean age of exposure to English was statistically significant (p = 0,019), with mean age of exposure to English in the ESL group (mean age = 2.82 ± 0.53) being higher than the mean age of exposure in the EFL group (mean age = 1.81 ± 1.53). However, this difference did not influence the results of the SAAT and DIN significantly.

CONCLUSION

The main finding was that selective auditory attention and speech-in-noise perception were not significantly affected in the ESL learners who participated in the study - learners who were recruited from private schools located in an urban area and thus from higher socio-economic status (SES) households. There is a need for additional research with a larger sample size to determine the selective auditory attention abilities and speech-in-noise perception skills of ESL learners in government-funded schools located in rural areas and from various socio-economic backgrounds.

Modulation of Cross-Language Activation During Bilingual Auditory Word Recognition: Effects of Language Experience but Not Competing Background Noise

Previous research has shown that as the level of background noise increases, auditory word recognition performance drops off more rapidly for bilinguals than monolinguals. This disproportionate bilingual deficit has often been attributed to a presumed increase in cross-language activation in noise, although no studies have specifically tested for such an increase. We propose two distinct mechanisms by which background noise could cause an increase in cross-language activation: a phonetically based account and an executive function-based account. We explore the evidence for the phonetically based account by comparing cognate facilitation effects for three groups of native English listeners (monolinguals, late (L2) learners of Spanish, and heritage Spanish speakers) and four noise conditions (no noise, speech-shaped noise, English two-talker babble, and Spanish two-talker babble) during an auditory lexical decision task in English. By examining word recognition in the dominant language, the role of language control mechanisms is minimized, and by examining three different types of competing noise, the role of energetic vs. informational masking can be assessed. Contrary to predictions, we find no evidence that background noise modulates cross-language activation; cognate facilitation is constant across the four noise conditions. Instead, several indices of word recognition performance are found to correlate with aspects of linguistic experience: (1) The magnitude of the cognate facilitation effect is correlated with heritage listeners' self-ratings of Spanish proficiency; (2) Overall noise deficits are marginally larger for heritage listeners with lower English vocabulary scores; (3) Heritage listeners' Spanish self-ratings predict their magnitude of informational masking; (4) For all bilinguals, the degree of masking incurred in both English and Spanish two-talker babble is correlated with self-reported daily exposure to Spanish; and (5) The degree of masking incurred by Spanish babble is correlated with Spanish vocabulary knowledge. The results enrich our understanding of auditory word recognition in heritage speakers in particular and provide evidence that informational masking is most subject to modulation due to variation in linguistic experience. It remains to be seen whether cross-language activation is modulated by noise when the target language is the less dominant one.

Learning and bilingualism in challenging listening conditions: How challenging can it be?

When speech is presented in their second language (L2), bilinguals have more difficulties with speech perception in noise than monolinguals do. However, how noise affects speech perception of bilinguals in their first language (L1) is still unclear. In addition, it is not clear whether bilinguals' speech perception in challenging listening conditions is specific to the type of degradation, or whether there is a shared mechanism for bilingual speech processing under complex listening conditions. Therefore, the current study examined the speech perception of 60 Arabic-Hebrew bilinguals and a control group of native Hebrew speakers during degraded (speech in noise, vocoded speech) and quiet listening conditions. Between participant comparisons (comparing native Hebrew speakers and bilinguals' perceptual performance in L1) and within participant comparisons (perceptual performance of bilinguals in L1 and L2) were conducted. The findings showed that bilinguals in L1 had more difficulty in noisy conditions than their control counterparts did, even when performed like controls under favorable listening conditions. However, bilingualism did not hinder language learning mechanisms. Bilinguals in L1 outperformed native Hebrew speakers in the perception of vocoded speech, demonstrating more extended learning processes. Bilinguals' perceptual performance in L1 versus L2 varied by task complexity. Correlation analyses revealed that bilinguals who coped better with noise degradation were more successful in perceiving the vocoding distortion. Together, these results provide insights into the mechanisms that contribute to speech perceptual performance in challenging listening conditions and suggest that bilinguals' language proficiency and age of language acquisition are not the only factors that affect performance. Rather, duration of exposure to languages, co-activation, and the ability to benefit from exposure to novel stimuli appear to affect the perceptual performance of bilinguals, even when operating in their dominant language. Our findings suggest that bilinguals use a shared mechanism for speech processing under challenging listening conditions.

Verification of a Mobile Psychoacoustic Test System

Many hearing difficulties can be explained as a loss of audibility, a problem easily detected and treated using standard audiological procedures. Yet, hearing can be much poorer (or more impaired) than audibility predicts because of deficits in the suprathreshold mechanisms that encode the rapidly changing, spectral, temporal, and binaural aspects of the sound. The ability to evaluate these mechanisms requires well-defined stimuli and strict adherence to rigorous psychometric principles. This project reports on the comparison between a laboratory-based and a mobile system's results for psychoacoustic assessment in adult listeners with normal hearing. A description of both systems employed is provided. Psychoacoustic tests include frequency discrimination, amplitude modulation detection, binaural encoding, and temporal gap detection. Results reported by the mobile system were not significantly different from those collected with the laboratory-based system for most of the tests and were consistent with those reported in the literature. The mobile system has the potential to be a feasible option for the assessment of suprathreshold auditory encoding abilities.

Development Of Speech Material For An Armenian Speech Recognition Threshold Test

Introduction — For the Armenian language, no standardized audiometric speech perception test is available. The purpose of this research was to develop, digitally record and evaluate an Armenian multisyllabic speech audiometry test, which can be used to measure speech recognition thresholds in Armenian native speakers. Material and Methods — To create a homogeneous multisyllabic speech corpus, Armenian numerals from 10-100 with 2-4 syllables were selected as general sample and digitally recorded by a female native Armenian speaker. For equalizing the speech recognition threshold between the test items, the speech discrimination function for each numeral was subsequently evaluated by five normal hearing native Armenian listeners in an experimental study. Results — Based on the phonemic structure of the Armenian language, 20 phonemically homogeneous test lists were created. The phoneme distributions of each test list correlated significantly and positively with that of the general sample (all Pearson moment correlation coefficients >0.960; all ps <0.001). Comparison of the phoneme distributions of test lists to that of the Armenian language showed that the test lists represent the language corpus quite well. After adjusting for actual threshold levels, speech discrimination functions are comparable between all numerals used. Conclusion — The developed test lists are a phonetically homogenous representation of the Armenian language and serve as an appropriated base for future clinical measurements of speech recognition threshold in Armenian speaking listeners.

Development of an Australian behavioural method for assessing listening task difficulty at high speech intelligibility levels

OBJECTIVE

To develop and validate an Australian version of a behavioural test for assessing listening task difficulty at high speech intelligibility levels.

DESIGN

In the SWIR-Aus test, listeners perform two tasks: identify the last word of each of seven sentences in a list and recall the identified words after each list. First, the test material was developed by creating seven-sentence lists with similar final-word features. Then, for the validation, participant's performance on the SWIR-Aus test was compared when a binary mask noise reduction algorithm was on and off.

STUDY SAMPLE

All participants in this study had normal hearing thresholds. Nine participants (23.8-56.0 years) participated in the characterisation of the speech material. Another thirteen participants (18.4-59.1 years) participated in a pilot test to determine the SNR to use at the validation stage. Finally, twenty-four new participants (20.0-56.9 years) participated in the validation of the test.

RESULTS

The results of the validation of the test showed that recall and identification scores were significantly better when the binary mask noise reduction algorithm was on compared to off.

CONCLUSIONS

The SWIR-Aus test was developed using Australian speech material and can be used for assessing task difficulty at high speech intelligibility levels.

Auditory function and prevalence of specific ear and hearing related pathologies in the general population at age 70

Objective: To describe the auditory function in early old age in detail based on both psychoacoustic and physiological measures, and to investigate the prevalence of specific audiological and otological pathologies.Design: An unscreened subsample from a population-based geriatric investigation was examined with otoscopy; tympanometry; pure-tone audiometry; word-recognition-in-noise test; distortion-product otoacoustic emissions; and auditory-evoked brainstem responses. Audiometric subtypes and diagnoses were established based on set criteria. The association between word scores and ABR was examined with linear regression analysis.Study Sample: 251 persons aged 70 (113 men, 138 women, born in 1944) that were representative of the inhabitants of the city of Gothenburg.Results: The prevalence of conductive pathology was 2% versus 49% for cochlear and 2% for auditory-neural pathology. Four percent had indeterminate type. Cochlear dysfunction was present in the majority of ears and around 20% performed worse-than-expected on speech testing. Poor performance on the speech in noise test was associated with prolonged interpeak latency interval of ABR waves I-V.Conclusion: Specific otological and audiological pathologies, other than cochlear hearing loss, are rare in the general population at age 70. Additionally, there is subtle evidence of age-related decline of the auditory nerve. Longitudinal follow-up would be of great interest.

Effects of hearing loss and language proficiency on speech intelligibility over radio transmission with tactical communication devices

Objective: Study the effects of hearing loss and language proficiency in a speech task over radio transmission.Design: Four TCAPS device conditions (2 models × 2 talk-through modes) were investigated with the Modified Rhyme Test (MRT) conducted in talker-listener pairs immersed in 85-dBA noise. Speech quality ratings and preferred radio volume levels were also collected.Study sample: Thirty-six participants divided into three groups (control, non-fluent, hearing-impaired) took part in the experiment. Participants acted as talkers and listeners when paired with a unique standard individual (fluent and normal hearing) of the same gender.Results: MRT scores were significantly lower in many device conditions when the non-fluent group of participants acted as listeners and talkers and when the hearing-impaired participants acted as listeners, compared to the control group. MRT results were also consistently poorer with one device configured for bone-conducted voice pick-up in the occluded ear compared to another one equipped with an external mouth microphone. Talk-through settings had little effect. MRT results were reflected in the subjective quality ratings. Participants with hearing loss used higher radio volume levels.Conclusions: Language proficiency, hearing loss and method of sensing the talker's voice are key issues to consider with TCAPS devices.

The effect of language, spatial factors, masker type and memory span on speech-in-noise thresholds in sequential bilingual children

This study considers whether bilingual children listening in a second language are among those on which higher processing and cognitive demands are placed when noise is present. Forty-four Swedish sequential bilingual 15 year-olds were given memory span and vocabulary assessments in their first and second language (Swedish and English). First and second language speech reception thresholds (SRTs) at 50% intelligibility for numbers and colors presented in noise were obtained using an adaptive procedure. The target sentences were presented in simulated, virtual classroom acoustics, masked by either 16-talker multi-talker babble noise (MTBN) or speech shaped noise (SSN), positioned either directly in front of the listener (collocated with the target speech), or spatially separated from the target speech by 90° to either side. Main effects in the Spatial and Noise factors indicated that intelligibility was 3.8 dB lower in collocated conditions and 2.9 dB lower in MTBN conditions. SRTs were unexpectedly higher by 0.9 dB in second language conditions. Memory span significantly predicted 17% of the variance in the second language SRTs, and 9% of the variance in first language SRTs, indicating the possibility that the SRT task places higher cognitive demands when listening to second language speech than when the target is in the listener's first language.

Diagnosing and Screening in a Minority Language: A Validation Study

PURPOSE

The Turkish Digit Triplet Test for hearing self-screening purposes and the Turkish Matrix Test (TURMatrix) for follow-up hearing diagnostics offer an automated closed-set response format where patients respond by choosing from response alternatives. Their applicability for testing Turkish-speaking patients in their native language by German audiologists with different Turkish language skills was investigated.

METHOD

Tests were composed of spoken numbers (Turkish Digit Triplet Test) or sentences (TURMatrix). For 49 participants differing in hearing ability, speech reception thresholds (SRTs) in noise and quiet were obtained, for the TURMatrix with either the open- or closed-set response format, by audiologists with and without Turkish language skills, respectively.

RESULTS

SRTs of both tests correlate closely with each other as well as with hearing ability, but not as closely as individual SRTs in quiet with hearing ability. SRTs in noise of listeners with normal hearing were about 0.7 dB lower for the closed-set than for the open-set response format.

CONCLUSIONS

The 2 tests yield comparable results and are applicable to professionals without suitable language skills. For the closed-set response format of the TURMatrix, literacy is crucial and supplemental (visual) cues improve performance. Speech audiometry in noise should assess suprathreshold processing deficits independently from language proficiency in the majority language.

A simulation framework for auditory discrimination experiments: Revealing the importance of across-frequency processing in speech perception

A framework for simulating auditory discrimination experiments, based on an approach from Schädler, Warzybok, Hochmuth, and Kollmeier [(2015). Int. J. Audiol. 54, 100-107] which was originally designed to predict speech recognition thresholds, is extended to also predict psychoacoustic thresholds. The proposed framework is used to assess the suitability of different auditory-inspired feature sets for a range of auditory discrimination experiments that included psychoacoustic as well as speech recognition experiments in noise. The considered experiments were 2 kHz tone-in-broadband-noise simultaneous masking depending on the tone length, spectral masking with simultaneously presented tone signals and narrow-band noise maskers, and German Matrix sentence test reception threshold in stationary and modulated noise. The employed feature sets included spectro-temporal Gabor filter bank features, Mel-frequency cepstral coefficients, logarithmically scaled Mel-spectrograms, and the internal representation of the Perception Model from Dau, Kollmeier, and Kohlrausch [(1997). J. Acoust. Soc. Am. 102(5), 2892-2905]. The proposed framework was successfully employed to simulate all experiments with a common parameter set and obtain objective thresholds with less assumptions compared to traditional modeling approaches. Depending on the feature set, the simulated reference-free thresholds were found to agree with-and hence to predict-empirical data from the literature. Across-frequency processing was found to be crucial to accurately model the lower speech reception threshold in modulated noise conditions than in stationary noise conditions.

Development and evaluation of the Turkish matrix sentence test

OBJECTIVES

The Turkish matrix sentence test, TURMatrix, was developed for precise, internationally comparable speech intelligibility testing.

DESIGN

The TURMatrix comprises a base matrix of ten well-known Turkish names, numbers, adjectives, objects, verbs, from which syntactically fixed sentences were randomly composed. Test conduction may be in an open-set (standard), or closed-set response format. Homogeneity in intelligibility of the test material was optimized by applying level adaptations (maximal ± 3 dB) based on word-specific speech reception thresholds (SRTs). Test list equivalence was verified and reference values were determined.

STUDY SAMPLE

Thirty-eight native listeners of Turkish with normal hearing.

RESULTS

After training, mean SRT and slope of the final test lists were -8.3 ± 0.2 dB SNR and 14.1 ± 1.0%/dB, respectively (fixed SNR measurements; inter-list variability). For adaptive measurements, average across listeners was -7.2 ± 0.7 dB SNR in the open-set and -7.9 ± 0.7 dB SNR in the closed-set response format. Mean SRT for adaptive measurements in the open-set response format in quiet was 20.3 ± 4.1 dB. Individual SRTs in quiet correlated more closely with audiograms than with SRTs in noise.

CONCLUSIONS

The TURMatrix was developed according to European standards and provides reliable speech intelligibility measurements in noise and quiet.