Mismatch Responses to Speech Contrasts in Preschoolers with and without Developmental Language Disorder.

This study compared cortical responses to speech in preschoolers with typical language development (TLD) and with Developmental Language Disorder (DLD). We investigated whether top-down language effects modulate speech perception in young children in an adult-like manner. We compared cortical mismatch responses (MMRs) during the passive perception of speech contrasts in three groups of participants: preschoolers with TLD (n = 11), preschoolers with DLD (n = 16), and adults (n = 20). We also measured children's phonological skills and investigated whether they are associated with the cortical discrimination of phonemic changes involving different linguistic complexities. The results indicated top-down language effects in adults, with enhanced cortical discrimination of lexical stimuli but not of non-words. In preschoolers, the TLD and DLD groups did not differ in the MMR measures, and no top-down effects were detected. Moreover, we found no association between MMRs and phonological skills, even though the DLD group's phonological skills were significantly lower. Our findings suggest that top-down language modulations in speech discrimination may not be present during early childhood, and that children with DLD may not exhibit cortical speech perception deficits. The lack of association between phonological and MMR measures indicates that further research is needed to understand the link between language skills and cortical activity in preschoolers.

Bilingual Mandarin-English preschoolers' spoken narrative skills and contributing factors: A remote online story-retell study.

This study examined the spoken narrative skills of a group of bilingual Mandarin-English speaking 3-6-year-olds (N = 25) in Australia, using a remote online story-retell task. Bilingual preschoolers are an understudied population, especially those who are speaking typologically distinct languages such as Mandarin and English which have fewer structural overlaps compared to language pairs that are typologically closer, reducing cross-linguistic positive transfer. We examined these preschoolers' spoken narrative skills as measured by macrostructures (the global organization of a story) and microstructures (linguistic structures, e.g., total number of utterances, nouns, verbs, phrases, and modifiers) across and within each language, and how various factors such as age and language experiences contribute to individual variability. The results indicate that our bilingual preschoolers acquired spoken narrative skills similarly across their two languages, i.e., showing similar patterns of productivity for macrostructure and microstructure elements in both of their two languages. While chronological age was positively correlated with macrostructures in both languages (showing developmental effects), there were no significant correlations between measures of language experiences and the measures of spoken narrative skills (no effects for language input/output). The findings suggest that although these preschoolers acquire two typologically diverse languages in different learning environments, Mandarin at home with highly educated parents, and English at preschool, they displayed similar levels of oral narrative skills as far as these macro-/micro-structure measures are concerned. This study provides further evidence for the feasibility of remote online assessment of preschoolers' narrative skills.

Speech modifications in interactive speech: effects of age, sex and noise type.

When attempting to maintain conversations in noisy communicative settings, talkers typically modify their speech to make themselves understood by the listener. In this study, we investigated the impact of background interference type and talker age on speech adaptations, vocal effort and communicative success. We measured speech acoustics (articulation rate, mid-frequency energy, fundamental frequency), vocal effort (correlation between mid-frequency energy and fundamental frequency) and task completion time in 114 participants aged 8-80 years carrying out an interactive problem-solving task in good and noisy listening conditions (quiet, non-speech noise, background speech). We found greater changes in fundamental frequency and mid-frequency energy in non-speech noise than in background speech and similar reductions in articulation rate in both. However, older participants (50+ years) increased vocal effort in both background interference types, whereas younger children (less than 13 years) increased vocal effort only in background speech. The presence of background interference did not lead to longer task completion times. These results suggest that when the background interference involves a higher cognitive load, as in the case of other speech of other talkers, children and older talkers need to exert more vocal effort to ensure successful communication. We discuss these findings within the communication effort framework. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part II)'.

Functional brain alterations following mild-to-moderate sensorineural hearing loss in children.

Auditory deprivation in the form of deafness during development leads to lasting changes in central auditory system function. However, less is known about the effects of mild-to-moderate sensorineural hearing loss (MMHL) during development. Here, we used a longitudinal design to examine late auditory evoked responses and mismatch responses to nonspeech and speech sounds for children with MMHL. At Time 1, younger children with MMHL (8-12 years; n = 23) showed age-appropriate mismatch negativities (MMNs) to sounds, but older children (12-16 years; n = 23) did not. Six years later, we re-tested a subset of the younger (now older) children with MMHL (n = 13). Children who had shown significant MMNs at Time 1 showed MMNs that were reduced and, for nonspeech, absent at Time 2. Our findings demonstrate that even a mild-to-moderate hearing loss during early-to-mid childhood can lead to changes in the neural processing of sounds in late childhood/adolescence.

Intelligibility of conversational and clear speech in young and older talkers as perceived by young and older listeners.

A related paper [Hazan, Tuomainen, Tu, Kim, Davis, Brungart, and Sheffield. (2018b). Hear. Res. 369, 33-41] showed that, for young adult listeners, speech produced by older adults was less intelligible than the speech of young adults but both talker groups improved the intelligibility of their speech via clear speech modifications. Here, this study was extended to include older listeners with/without presbycusis. The results showed that for older listeners, speech produced by older adults was less intelligible than the speech of young adults and scores improved in the clear speech condition. The best predictor of intelligibility was the amount of energy in the mid-frequency range of the spectrum.

Impaired frequency selectivity and sensitivity to temporal fine structure, but not envelope cues, in children with mild-to-moderate sensorineural hearing loss.

Psychophysical thresholds were measured for 8-16 year-old children with mild-to-moderate sensorineural hearing loss (MMHL; N = 46) on a battery of auditory processing tasks that included measures designed to be dependent upon frequency selectivity and sensitivity to temporal fine structure (TFS) or envelope cues. Children with MMHL who wore hearing aids were tested in both unaided and aided conditions, and all were compared to a group of normally hearing (NH) age-matched controls. Children with MMHL performed more poorly than NH controls on tasks considered to be dependent upon frequency selectivity, sensitivity to TFS, and speech discrimination (/bɑ/-/dɑ/), but not on tasks measuring sensitivity to envelope cues. Auditory processing deficits remained regardless of age, were observed in both unaided and aided conditions, and could not be attributed to differences in nonverbal IQ or attention between groups. However, better auditory processing in children with MMHL was predicted by better audiometric thresholds and, for aided tasks only, higher levels of maternal education. These results suggest that, as for adults with MMHL, children with MMHL may show deficits in frequency selectivity and sensitivity to TFS, but sensitivity to the envelope may remain intact.

Clear speech adaptations in spontaneous speech produced by young and older adults.

The study investigated the speech adaptations by older adults (OA) with and without age-related hearing loss made to communicate effectively in challenging communicative conditions. Acoustic analyses were carried out on spontaneous speech produced during a problem-solving task (diapix) carried out by talker pairs in different listening conditions. There were 83 talkers of Southern British English. Fifty-seven talkers were OAs aged 65-84, 30 older adults with normal hearing (OANH), and 27 older adults with hearing loss (OAHL) [mean pure tone average (PTA) 0.250-4 kHz: 27.7 dB HL]. Twenty-six talkers were younger adults (YA) aged 18-26 with normal hearing. Participants were recorded while completing the diapix task with a conversational partner (YA of the same sex) when (a) both talkers heard normally (NORM), (b) the partner had a simulated hearing loss, and (c) both talkers heard babble noise. Irrespective of hearing status, there were age-related differences in some acoustic characteristics of YA and OA speech produced in NORM, most likely linked to physiological factors. In challenging conditions, while OANH talkers typically patterned with YA talkers, OAHL talkers made adaptations more consistent with an increase in vocal effort. The study suggests that even mild presbycusis in healthy OAs can affect the speech adaptations made to maintain effective communication.

How do aging and age-related hearing loss affect the ability to communicate effectively in challenging communicative conditions?

This study investigated the relation between the intelligibility of conversational and clear speech produced by older and younger adults and (a) the acoustic profile of their speech (b) communication effectiveness. Speech samples from 30 talkers from the elderLUCID corpus were used: 10 young adults (YA), 10 older adults with normal hearing (OANH) and 10 older adults with presbycusis (OAHL). Samples were extracted from recordings made while participants completed a problem-solving cooperative task (diapix) with a conversational partner who could either hear them easily (NORM) or via a simulated hearing loss (HLS), which led talkers to naturally adopt a clear speaking style. In speech-in-noise listening experiments involving 21 young adult listeners, speech samples by OANH and OAHL were rated and perceived as less intelligible than those of YA talkers. HLS samples were more intelligible than NORM samples, with greater improvements in intelligibility across conditions seen for OA speech. The presence of presbycusis affected (a) the clear speech strategies adopted by OAHL talkers and (b) task effectiveness: OAHL talkers showed some adaptations consistent with an increase in vocal effort, and it took them significantly longer than the YA group to complete the diapix task. The relative energy in the 1-3 kHz frequency region of the long-term average spectrum was the feature that best predicted: (a) the intelligibility of speech samples, and (b) task transaction time in the HLS condition. Overall, our study suggests that spontaneous speech produced by older adults is less intelligible in babble noise, probably due to less energy present in the 1-3 kHz frequency range rich in acoustic cues. Even mild presbycusis in 'healthy aged' adults can affect the dynamic adaptations in speech that are beneficial for effective communication.

Auditory processing deficits are sometimes necessary and sometimes sufficient for language difficulties in children: Evidence from mild to moderate sensorineural hearing loss.

There is a general consensus that many children and adults with dyslexia and/or specific language impairment display deficits in auditory processing. However, how these deficits are related to developmental disorders of language is uncertain, and at least four categories of model have been proposed: single distal cause models, risk factor models, association models, and consequence models. This study used children with mild to moderate sensorineural hearing loss (MMHL) to investigate the link between auditory processing deficits and language disorders. We examined the auditory processing and language skills of 46, 8-16year-old children with MMHL and 44 age-matched typically developing controls. Auditory processing abilities were assessed using child-friendly psychophysical techniques in order to obtain discrimination thresholds. Stimuli incorporated three different timescales (µs, ms, s) and three different levels of complexity (simple nonspeech tones, complex nonspeech sounds, speech sounds), and tasks required discrimination of frequency or amplitude cues. Language abilities were assessed using a battery of standardised assessments of phonological processing, reading, vocabulary, and grammar. We found evidence that three different auditory processing abilities showed different relationships with language: Deficits in a general auditory processing component were necessary but not sufficient for language difficulties, and were consistent with a risk factor model; Deficits in slow-rate amplitude modulation (envelope) detection were sufficient but not necessary for language difficulties, and were consistent with either a single distal cause or a consequence model; And deficits in the discrimination of a single speech contrast (/bɑ/ vs /dɑ/) were neither necessary nor sufficient for language difficulties, and were consistent with an association model. Our findings suggest that different auditory processing deficits may constitute distinct and independent routes to the development of language difficulties in children.

Language Development and Impairment in Children With Mild to Moderate Sensorineural Hearing Loss.

Purpose: The goal of this study was to examine language development and factors related to language impairments in children with mild to moderate sensorineural hearing loss (MMHL). Method: Ninety children, aged 8-16 years (46 children with MMHL; 44 aged-matched controls), were administered a battery of standardized language assessments, including measures of phonological processing, receptive and expressive vocabulary and grammar, word and nonword reading, and parental report of communication skills. Group differences were examined after controlling for nonverbal ability. Results: Children with MMHL performed as well as controls on receptive vocabulary and word and nonword reading. They also performed within normal limits, albeit significantly worse than controls, on expressive vocabulary, and on receptive and expressive grammar, and worse than both controls and standardized norms on phonological processing and parental report of communication skills. However, there was considerable variation in performance, with 26% showing evidence of clinically significant oral or written language impairments. Poor performance was not linked to severity of hearing loss nor age of diagnosis. Rather, outcomes were related to nonverbal ability, maternal education, and presence/absence of family history of language problems. Conclusions: Clinically significant language impairments are not an inevitable consequence of MMHL. Risk factors appear to include lower maternal education and family history of language problems, whereas nonverbal ability may constitute a protective factor.

Identification of fluency and word-finding difficulty in samples of children with diverse language backgrounds.

BACKGROUND: Stuttering and word-finding difficulty (WFD) are two types of communication difficulty that occur frequently in children who learn English as an additional language (EAL), as well as those who only speak English. The two disorders require different, specific forms of intervention. Prior research has described the symptoms of each type of difficulty. This paper describes the development of a non-word repetition test (UNWR), applicable across languages, that was validated by comparing groups of children identified by their speech and language symptoms as having either stuttering or WFD. AIMS: To evaluate whether non-word repetition scores using the UNWR test distinguished between children who stutter and those who have a WFD, irrespective of the children's first language. METHODS & PROCEDURES: UNWR was administered to ninety-six 4-5-year-old children attending UK schools (20.83% of whom had EAL). The children's speech samples in English were assessed for symptoms of stuttering and WFD. UNWR scores were calculated. OUTCOMES & RESULTS: Regression models were fitted to establish whether language group (English only/EAL) and symptoms of (1) stuttering and (2) WFD predicted UNWR scores. Stuttering symptoms predicted UNWR, whereas WFD did not. These two findings suggest that UNWR scores dissociate stuttering from WFD. There were no differences between monolingual English-speakers and children who had EAL. CONCLUSIONS & IMPLICATIONS: UNWR scores distinguish between stuttering and WFD irrespective of language(s) spoken, allowing future evaluation of a range of languages in clinics or schools.

Suprasegmental Characteristics of Spontaneous Speech Produced in Good and Challenging Communicative Conditions by Talkers Aged 9-14 Years.

Purpose: This study investigated the acoustic characteristics of spontaneous speech by talkers aged 9-14 years and their ability to adapt these characteristics to maintain effective communication when intelligibility was artificially degraded for their interlocutor. Method: Recordings were made for 96 children (50 female participants, 46 male participants) engaged in a problem-solving task with a same-sex friend; recordings for 20 adults were used as reference. The task was carried out in good listening conditions (normal transmission) and in degraded transmission conditions. Articulation rate, median fundamental frequency (f0), f0 range, and relative energy in the 1- to 3-kHz range were analyzed. Results: With increasing age, children significantly reduced their median f0 and f0 range, became faster talkers, and reduced their mid-frequency energy in spontaneous speech. Children produced similar clear speech adaptations (in degraded transmission conditions) as adults, but only children aged 11-14 years increased their f0 range, an unhelpful strategy not transmitted via the vocoder. Changes made by children were consistent with a general increase in vocal effort. Conclusion: Further developments in speech production take place during later childhood. Children use clear speech strategies to benefit an interlocutor facing intelligibility problems but may not be able to attune these strategies to the same degree as adults.

Do talkers produce less dispersed phoneme categories in a clear speaking style?

This study investigated whether adaptations made in clear speaking styles result in more discriminable phonetic categories than in a casual style. Multiple iterations of keywords with word-initial /s/-/ʃ/ were obtained from 40 adults in casual and clear speech via picture description. For centroids, cross-category distance increased in clear speech but with no change in within-category dispersion and no effect on discriminability. However, talkers produced fewer tokens with centroids in the ambiguous region for the /s/-/ʃ/ distinction. These results suggest that, whereas interlocutor feedback regarding communicative success may promote greater segmental adaptations, it is not necessary for some adaptation to occur.

Phonetic categorisation and cue weighting in adolescents with Specific Language Impairment (SLI).

This study investigates phonetic categorisation and cue weighting in adolescents and young adults with Specific Language Impairment (SLI). We manipulated two acoustic cues, vowel duration and F1 offset frequency, that signal word-final stop consonant voicing ([t] and [d]) in English. Ten individuals with SLI (14.0-21.4 years), 10 age-matched controls (CA; 14.6-21.9 years) and 10 non-matched adult controls (23.3-36.0 years) labelled synthetic CVC non-words in an identification task. The results showed that the adolescents and young adults with SLI were less consistent than controls in the identification of the good category representatives. The group with SLI also assigned less weight to vowel duration than the adult controls. However, no direct relationship between phonetic categorisation, cue weighting and language skills was found. These findings indicate that some individuals with SLI have speech perception deficits but they are not necessarily associated with oral language skills.

Auditory short-term memory trace formation for nonspeech and speech in SLI and dyslexia as indexed by the N100 and mismatch negativity electrophysiological responses.

This study investigates nonspeech and speech processing in specific language impairment (SLI) and dyslexia. We used a passive mismatch negativity (MMN) task to tap automatic brain responses and an active behavioural task to tap attended discrimination of nonspeech and speech sounds. Using the roving standard MMN paradigm, we varied the number of standards ('few' vs. 'many') to investigate the effect of sound repetition on N100 and MMN responses. The results revealed that the SLI group needed more repetitions than dyslexics and controls to create a strong enough sensory trace to elicit MMN. In contrast, in the behavioural task, we observed good discrimination of speech and nonspeech in all groups. The findings indicate that auditory processing deficits in SLI and dyslexia are dissociable and that memory trace formation may be implicated in SLI.

The effect of language immersion education on the preattentive perception of native and non-native vowel contrasts.

Proficiency in a second language (L2) may depend upon the age of exposure and the continued use of the mother tongue (L1) during L2 acquisition. The effect of early L2 exposure on the preattentive perception of native and non-native vowel contrasts was studied by measuring the mismatch negativity (MMN) response from 14-year-old children. The test group consisted of six Finnish children who had participated in English immersion education. The control group consisted of eight monolingual Finns. The subjects were presented with Finnish and English synthetic vowel contrasts. The aim was to see whether early exposure had resulted in the development of a new language-specific memory trace for the contrast phonemically irrelevant in L1. The results indicated that only the contrast with the largest acoustic distance elicited an MMN response in the Bilingual group, while the Monolingual group showed a response also to the native contrast. This may suggest that native-like memory traces for prototypical vowels were not formed in early language immersion.