The Effect of Intensified Language Exposure on Accommodating Talker Variability

Multiple talker processing in autistic adult listeners

Accommodating talker variability is a complex and multi-layered cognitive process. It involves shifting attention to the vocal characteristics of the talker as well as the linguistic content of their speech. Due to an interdependence between voice and phonological processing, multi-talker environments typically incur additional processing costs compared to single-talker environments. A failure or inability to efficiently distribute attention over multiple acoustic cues in the speech signal may have detrimental language learning consequences. Yet, no studies have examined effects of multi-talker processing in populations with atypical perceptual, social and language processing for communication, including autistic people. Employing a classic word-monitoring task, we investigated effects of talker variability in Australian English autistic (n = 24) and non-autistic (n = 28) adults. Listeners responded to target words (e.g., apple, duck, corn) in randomised sequences of words. Half of the sequences were spoken by a single talker and the other half by multiple talkers. Results revealed that autistic participants' sensitivity scores to accurately-spotted target words did not differ to those of non-autistic participants, regardless of whether they were spoken by a single or multiple talkers. As expected, the non-autistic group showed the well-established processing cost associated with talker variability (e.g., slower response times). Remarkably, autistic listeners' response times did not differ across single- or multi-talker conditions, indicating they did not show perceptual processing costs when accommodating talker variability. The present findings have implications for theories of autistic perception and speech and language processing.

The effect of study-abroad experience on lexical translation among interpreting students

This study investigates the impact of study-abroad experience (SAE) on lexical translation among 50 Chinese (L1)-English (L2) interpreting students. Participants were divided into two groups based on their experience abroad. Both groups consisted of 25 unbalanced L2 learners who were matched in age, working memory, length of interpreting training, and L2 proficiency. Bidirectional word translation recognition tasks, from L1 to L2 and L2 to L1, highlighted several key findings: (1) both groups were significantly more accurate and faster from L2 to L1 than in the reverse direction; (2) the study abroad (SA) group was more inclined to respond quickly at the risk of making errors, whereas the non-study abroad (NSA) group tended to be more cautious, prioritising accuracy over speed; (3) the SA group were more balanced and consistent in their performance across lexical translations in both directions than the NSA group. These results emphasise the potent effect of SAE in resolving bilinguals' language competition, especially in streamlining language switching, a cognitive process critical for interpreting students engaging daily with dual languages.

The Extent of Hearing Input Affects the Plasticity of the Auditory Cortex in Children With Hearing Loss: A Preliminary Study

PURPOSE

This study investigated to what extent residual hearing and rehabilitation options (e.g., hearing aids [HAs]) affect the auditory cortex in children with hearing loss.

METHOD

Twenty-one children with bilateral congenital sensorineural hearing loss who were candidates for cochlear implantation were recruited. Voxel-based morphometry analysis was conducted to assess the gray matter (GM) volume in the auditory cortex. Children's residual hearing was measured by pure-tone audiometry at different frequencies. Multiple linear regression models were conducted to examine the effects of residual hearing and the use of HAs on GM volume in the auditory cortex with the control of age and gender.

RESULTS

Children with more residual hearing at high frequencies had larger GM volume ratio (corrected by total intracranial volume) in the left Heschl's gyrus (r = -.545, p = .013). An interaction effect between residual hearing and the use of HAs suggested that the effect of residual hearing on GM ratio was moderated by the use of HAs (β = -.791, p = .020). Compared with children with less residual hearing, children who had more residual hearing benefited more from longer use of HAs in terms of a larger GM ratio.

CONCLUSIONS

Our preliminary findings highlight the impact of residual hearing on the neuroanatomy of the auditory cortex in children with hearing loss. Moreover, our results call for more auditory input via HAs for children with more residual hearing to preserve the auditory cortex before cochlear implantation. For children with less residual hearing who might receive limited benefit from HAs, an early cochlear implant would be necessary.

Accent, Comprehensibility, and Confidence in Second and Third Languages of Adolescents: How Do They Relate to Language Proficiency and Language Interactions?

PURPOSE

This study examines the degree to which adolescents in Iceland are judged by native Icelandic speakers to have a foreign accent both in Icelandic and in English, two languages that are learned under different conditions, as the community and school language, and through school and incidental exposure.

METHOD

Fifty-eight adolescents, 27 with Icelandic as their first language (L1), 21 as their second language (L2), and 10 as one of two L1s read passages in Icelandic and English. Twelve untrained native speakers of Icelandic rated the degree of foreign accent, comprehensibility, and confidence level and selected from multiple-choice options what they thought was the L1 of the speakers.

RESULTS

Significant group differences were found in Icelandic but not in English. L2 speakers had a significantly greater foreign accent than the other groups in Icelandic; however, there was substantial overlap with some L2 speakers judged to be native and some L1 speakers judged as nonnative. All groups had a significantly greater accent in English than in Icelandic. Accent was judged more sternly than comprehensibility and confidence and related differently to vocabulary proficiency.

CONCLUSIONS

Accent is typically not considered in studies of bilingual attainment in children for purposes of clinical assessment or educational placement but should be given closer attention. The study confirms previous findings that many young L2 learners have a detectable foreign accent. The overlap with L1 speakers also raises questions about the ideal of a native accent. More research is needed on how accent relates to bilingual and multilingual proficiency and on its impacts on comfort level, ease of communication, choice of language, and language exposure.

Onset Age of Language Acquisition Effects in a Foreign Language Context: Evidence from Chinese-English Bilingual Children

The present study examined the relationship between age of acquisition (AoA) and bilingual development for native Chinese children who learned English as a foreign language. A composite test measuring different aspects of language and cognitive skills in Chinese and English was administered on 85 Chinese native primary schoolers, who received bilingual instruction at different points of development (for Chinese, 0 ≤ AoA ≤ 7 years; for English, 2 ≤ AoA ≤ 10 years). Results found AoA constraints on the outcomes of L1 Chinese acquisition are significantly different from those for L2 English. Not all domains of bilingual skills follow the pattern of "the earlier, the better" in language development. Additionally, L1 AoA made unique contributions to L2 English learning. These findings contribute to our understanding on the nature of the AoA effect on bilingual learning.

English Consonant Identification in Multi-Talker Babble: Effects of Chinese-Native Listeners' English Experience

The identification of English consonants in quiet and multi-talker babble was examined for three groups of young adult listeners: Chinese in China, Chinese in the USA (CNU), and English-native listeners. As expected, native listeners outperformed non-native listeners. The two non-native groups had similar performance in quiet, whereas CNU listeners performed significantly better than Chinese in China listeners in babble. It is concluded that CNU listeners may benefit from English experience, for example, better use of temporal variation in noise and better capacity against informational masking, to perceive English consonants better in babble. Possible explanations regarding the differential noise effect on the three groups are discussed.

Discriminating Non-Native Segmental Length Contrasts Under Increased Task Demands

The present study examines how vulnerable perception of second language prosody is to increased task demands. German learners of Japanese, German non-learners without exposure to Japanese, and Japanese native listeners were tested in their ability to discriminate consonant length contrasts (compared to vowel length contrasts that served as a control condition). Memory load was increased by a longer inter-stimulus interval (2500 ms compared to 300 ms) and the demand on attention control was enhanced through the addition of the acoustic complexity of the stimuli (i.e., through a task-irrelevant pitch fall that occurred simultaneously with a consonant length contrast). The results showed high discrimination abilities, in all groups, when task demands were lowest. With increased task demands, only non-native listeners' discrimination abilities decreased: non-learners were strongly affected by both increased memory load and higher demand on attention control, while learners were only affected by the latter. The task-irrelevant acoustic complexity of the stimuli had a stronger impact on performance than increased memory load did. The findings suggest that second language learners established novel phonological representations but that the ability to use them could only be applied in the absence of distracting acoustic information. The non-native listeners' reduced sensitivity under increased task demands explains why even advanced learners still face difficulties in daily listening situations with numerous distractions.

Intonation and talker variability in the discrimination of Spanish lexical stress contrasts by Spanish, German and French listeners

The perception of stress is highly influenced by listeners' native language. In this research, the authors examined the effect of intonation and talker variability (here: phonetic variability) in the discrimination of Spanish lexical stress contrasts by native Spanish (N = 17), German (N = 21), and French (N = 27) listeners. Participants listened to 216 trials containing three Spanish disyllabic words, where one word carried a different lexical stress to the others. The listeners' task was to identify the deviant word in each trial (Odd-One-Out task). The words in the trials were produced by either the same talker or by two different talkers, and carried the same or varying intonation patterns. The German listeners' performance was lower compared to the Spanish listeners but higher than that of the French listeners. French listeners performed above chance level with and without talker variability, and performed at chance level when intonation variability was introduced. Results are discussed in the context of the stress "deafness" hypothesis.

Complexity, Training Paradigm Design, and the Contribution of Memory Subsystems to Grammar Learning

Although there is variability in nonnative grammar learning outcomes, the contributions of training paradigm design and memory subsystems are not well understood. To examine this, we presented learners with an artificial grammar that formed words via simple and complex morphophonological rules. Across three experiments, we manipulated training paradigm design and measured subjects' declarative, procedural, and working memory subsystems. Experiment 1 demonstrated that passive, exposure-based training boosted learning of both simple and complex grammatical rules, relative to no training. Additionally, procedural memory correlated with simple rule learning, whereas declarative memory correlated with complex rule learning. Experiment 2 showed that presenting corrective feedback during the test phase did not improve learning. Experiment 3 revealed that structuring the order of training so that subjects are first exposed to the simple rule and then the complex improved learning. The cumulative findings shed light on the contributions of grammatical complexity, training paradigm design, and domain-general memory subsystems in determining grammar learning success.

Poor phonetic perceivers are affected by cognitive load when resolving talker variability

Speech training paradigms aim to maximise learning outcomes by manipulating external factors such as talker variability. However, not all individuals may benefit from such manipulations because subject-external factors interact with subject-internal ones (e.g., aptitude) to determine speech perception and/or learning success. In a previous tone learning study, high-aptitude individuals benefitted from talker variability, whereas low-aptitude individuals were impaired. Because increases in cognitive load have been shown to hinder speech perception in mixed-talker conditions, it has been proposed that resolving talker variability requires cognitive resources. This proposal leads to the hypothesis that low-aptitude individuals do not use their cognitive resources as efficiently as those with high aptitude. Here, high- and low-aptitude subjects identified pitch contours spoken by multiple talkers under high and low cognitive load conditions established by a secondary task. While high-aptitude listeners outperformed low-aptitude listeners across load conditions, only low-aptitude listeners were impaired by increased cognitive load. The findings suggest that low-aptitude listeners either have fewer available cognitive resources or are poorer at allocating attention to the signal. Therefore, cognitive load is an important factor when considering individual differences in speech perception and training paradigms.