Auditory free classification of gender diverse speakersa).

Auditory attribution of speaker gender has historically been assumed to operate within a binary framework. The prevalence of gender diversity and its associated sociophonetic variability motivates an examination of how listeners perceptually represent these diverse voices. Utterances from 30 transgender (1 agender individual, 15 non-binary individuals, 7 transgender men, and 7 transgender women) and 30 cisgender (15 men and 15 women) speakers were used in an auditory free classification paradigm, in which cisgender listeners classified the speakers on perceived general similarity and gender identity. Multidimensional scaling of listeners' classifications revealed two-dimensional solutions as the best fit for general similarity classifications. The first dimension was interpreted as masculinity/femininity, where listeners organized speakers from high to low fundamental frequency and first formant frequency. The second was interpreted as gender prototypicality, where listeners separated speakers with fundamental frequency and first formant frequency at upper and lower extreme values from more intermediate values. Listeners' classifications for gender identity collapsed into a one-dimensional space interpreted as masculinity/femininity. Results suggest that listeners engage in fine-grained analysis of speaker gender that cannot be adequately captured by a gender dichotomy. Further, varying terminology used in instructions may bias listeners' gender judgements.

"They sure aren't from around here": Children's perception of accent distance in L1 and L2 varieties of English.

Children exhibit preferences for familiar accents early in life. However, they frequently have more difficulty distinguishing between first language (L1) accents than second language (L2) accents in categorization tasks. Few studies have addressed children's perception of accent strength, or the relation between accent strength and objective measures of pronunciation distance. To address these gaps, 6- and 12-year-olds and adults ranked talkers' perceived distance from the local accent (i.e., Midland American English). Rankings were compared with objective distance measures. Acoustic and phonetic distance measures were significant predictors of ladder rankings, but there was no evidence that children and adults significantly differed in their sensitivity to accent strength. Levenshtein Distance, a phonetic distance metric, was the strongest predictor of perceptual rankings for both children and adults. As a percept, accent strength has critical implications for social judgments, which determine real world social outcomes for talkers with non-local accents.

Revisiting the acoustics of speaker gender perception: A gender expansive perspective.

Examinations of speaker gender perception have primarily focused on the roles of fundamental frequency (fo) and formant frequencies from structured speech tasks using cisgender speakers. Yet, there is evidence to suggest that fo and formants do not fully account for listeners' perceptual judgements of gender, particularly from connected speech. This study investigated the perceptual importance of fo, formant frequencies, articulation, and intonation in listeners' judgements of gender identity and masculinity/femininity from spontaneous speech from cisgender male and female speakers as well as transfeminine and transmasculine speakers. Stimuli were spontaneous speech samples from 12 speakers who are cisgender (6 female and 6 male) and 12 speakers who are transgender (6 transfeminine and 6 transmasculine). Listeners performed a two-alternative forced choice (2AFC) gender identification task and masculinity/femininity rating task in two experiments that manipulated which acoustic cues were available. Experiment 1 confirmed that fo and formant frequency manipulations were insufficient to alter listener judgements across all speakers. Experiment 2 demonstrated that articulatory cues had greater weighting than intonation cues on the listeners' judgements when the fo and formant frequencies were in a gender ambiguous range. These findings counter the assumptions that fo and formant manipulations are sufficient to effectively alter perceived speaker gender.

Intelligibility of medically related sentences in quiet, speech-shaped noise, and hospital noise.

Noise in healthcare settings, such as hospitals, often exceeds levels recommended by health organizations. Although researchers and medical professionals have raised concerns about the effect of these noise levels on spoken communication, objective measures of behavioral intelligibility in hospital noise are lacking. Further, no studies of intelligibility in hospital noise used medically relevant terminology, which may differentially impact intelligibility compared to standard terminology in speech perception research and is essential for ensuring ecological validity. Here, intelligibility was measured using online testing for 69 young adult listeners in three listening conditions (i.e., quiet, speech-shaped noise, and hospital noise: 23 listeners per condition) for four sentence types. Three sentence types included medical terminology with varied lexical frequency and familiarity characteristics. A final sentence set included non-medically related sentences. Results showed that intelligibility was negatively impacted by both noise types with no significant difference between the hospital and speech-shaped noise. Medically related sentences were not less intelligible overall, but word recognition accuracy was significantly positively correlated with both lexical frequency and familiarity. These results support the need for continued research on how noise levels in healthcare settings in concert with less familiar medical terminology impact communications and ultimately health outcomes.

How pronunciation distance impacts word recognition in children and adults.

Although unfamiliar accents can pose word identification challenges for children and adults, few studies have directly compared perception of multiple nonnative and regional accents or quantified how the extent of deviation from the ambient accent impacts word identification accuracy across development. To address these gaps, 5- to 7-year-old children's and adults' word identification accuracy with native (Midland American, British, Scottish), nonnative (German-, Mandarin-, Japanese-accented English) and bilingual (Hindi-English) varieties (one talker per accent) was tested in quiet and noise. Talkers' pronunciation distance from the ambient dialect was quantified at the phoneme level using a Levenshtein algorithm adaptation. Whereas performance was worse on all non-ambient dialects than the ambient one, there were only interactions between talker and age (child vs adult or across age for the children) for a subset of talkers, which did not fall along the native/nonnative divide. Levenshtein distances significantly predicted word recognition accuracy for adults and children in both listening environments with similar impacts in quiet. In noise, children had more difficulty overcoming pronunciations that substantially deviated from ambient dialect norms than adults. Future work should continue investigating how pronunciation distance impacts word recognition accuracy by incorporating distance metrics at other levels of analysis (e.g., phonetic, suprasegmental).

Development of unfamiliar accent comprehension continues through adolescence.

School-age children's understanding of unfamiliar accents is not adult-like and the age at which this ability fully matures is unknown. To address this gap, eight- to fifteen-year-old children's (n = 74) understanding of native- and non-native-accented sentences in quiet and noise was assessed. Children's performance was adult-like by eleven to twelve years for the native accent in noise and by fourteen to fifteen years for the non-native accent in quiet. However, fourteen- to fifteen-year old's performance was not adult-like for the non-native accent in noise. Thus, adult-like comprehension of unfamiliar accents may require greater exposure to linguistic variability or additional cognitive-linguistic growth.

A relationship between processing speech in noise and dysarthric speech.

There is substantial individual variability in understanding speech in adverse listening conditions. This study examined whether a relationship exists between processing speech in noise (environmental degradation) and dysarthric speech (source degradation), with regard to intelligibility performance and the use of metrical stress to segment the degraded speech signals. Ninety native speakers of American English transcribed speech in noise and dysarthric speech. For each type of listening adversity, transcriptions were analyzed for proportion of words correct and lexical segmentation errors indicative of stress cue utilization. Consistent with the hypotheses, intelligibility performance for speech in noise was correlated with intelligibility performance for dysarthric speech, suggesting similar cognitive-perceptual processing mechanisms may support both. The segmentation results also support this postulation. While stress-based segmentation was stronger for speech in noise relative to dysarthric speech, listeners utilized metrical stress to parse both types of listening adversity. In addition, reliance on stress cues for parsing speech in noise was correlated with reliance on stress cues for parsing dysarthric speech. Taken together, the findings demonstrate a preference to deploy the same cognitive-perceptual strategy in conditions where metrical stress offers a route to segmenting degraded speech.

Nonnative Accent Discrimination with Words and Sentences.

BACKGROUND: Accent detection studies have shown native listeners to be highly sensitive to the presence of nonnative accents. This study examined the robustness of this sensitivity. METHODS: We evaluated listeners' accent discrimination performance when presented with a stimulus set consisting of multiple nonnative accents, as well as words and sentences that were unique in each trial. Listeners heard pairs of talkers reading the same word or sentence and indicated whether the talkers' native languages were the same or different. Talkers included two native talkers and six nonnative talkers from three native language backgrounds. RESULTS: Listeners were highly sensitive to the difference between native and nonnative accents, confirming earlier findings, but were much less sensitive to the difference between two nonnative accents. Furthermore, while stimulus length affected listeners' sensitivity to the difference between native and nonnative accents, this factor had a minimal effect on their sensitivity to the difference between two nonnative accents. CONCLUSION: The findings suggest that task and stimulus characteristics have a significant effect on the degree of sensitivity to nonnative accents.

Perception of Nonnative-accented Sentences by 5- to 8-Year-olds and Adults: The Role of Phonological Processing Skills.

To acquire language and successfully communicate in multicultural and multilingual societies, children must learn to understand speakers with various accents and dialects. This study investigated adults' and 5- to 8-year-old children's perception of native- and nonnative-accented English sentences in noise. Participants' phonological memory and phonological awareness were assessed to investigate factors associated with individual differences in word recognition. Although both adults and children performed less accurately with nonnative talkers than native talkers, children showed greater performance decrements. Further, phonological memory was more closely tied to perception of native talkers whereas phonological awareness was more closely related to perception of nonnative talkers. These results suggest that the ability to recognize words produced in unfamiliar accents continues to develop beyond the early school-age years. Additionally, the linguistic skills most related to word recognition in adverse listening conditions may differ depending on the source of the challenge (i.e., noise, talker, or a combination).

Individual differences in the perception of regional, nonnative, and disordered speech varieties.

Speech perception abilities vary substantially across listeners, particularly in adverse conditions including those stemming from environmental degradation (e.g., noise) or from talker-related challenges (e.g., nonnative or disordered speech). This study examined adult listeners' recognition of words in phrases produced by six talkers representing three speech varieties: a nonnative accent (Spanish-accented English), a regional dialect (Irish English), and a disordered variety (ataxic dysarthria). Semantically anomalous phrases from these talkers were presented in a transcription task and intelligibility scores, percent words correct, were compared across the three speech varieties. Three cognitive-linguistic areas-receptive vocabulary, cognitive flexibility, and inhibitory control of attention-were assessed as possible predictors of individual word recognition performance. Intelligibility scores for the Spanish accent were significantly correlated with scores for the Irish English and ataxic dysarthria. Scores for the Irish English and dysarthric speech, in contrast, were not correlated. Furthermore, receptive vocabulary was the only cognitive-linguistic assessment that significantly predicted intelligibility scores. These results suggest that, rather than a global skill of perceiving speech that deviates from native dialect norms, listeners may possess specific abilities to overcome particular types of acoustic-phonetic deviation. Furthermore, vocabulary size offers performance benefits for intelligibility of speech that deviates from one's typical dialect norms.

Children's perception of nonnative-accented sentences in noise and quiet.

Adult listeners' word recognition is remarkably robust under a variety of adverse listening conditions. However, the combination of two simultaneous listening challenges (e.g., nonnative speaker in noise) can cause significant word recognition decrements. This study investigated how talker-related (native vs nonnative) and environment-related (noise vs quiet) adverse conditions impact children's and adults' word recognition. Five- and six-year-old children and adults identified sentences produced by one native and one nonnative talker in both quiet and noise-added conditions. Children's word recognition declined significantly more than adults' in conditions with one source of listening adversity (i.e., native speaker in noise or nonnative speaker in quiet). Children's performance when the listening challenges were combined (nonnative talker in noise) was particularly poor. Immature speech-in-noise perception may be a result of children's difficulties with signal segregation or selective attention. In contrast, the explanation for children's difficulty in the mapping of unfamiliar pronunciations to known words in quiet listening conditions must rest on children's limited cognitive or linguistic skills and experiences. These results demonstrate that children's word recognition abilities under both environmental- and talker-related adversity are still developing in the early school-age years.

Relationship between listeners' nonnative speech recognition and categorization abilities.

Enhancement of the perceptual encoding of talker characteristics (indexical information) in speech can facilitate listeners' recognition of linguistic content. The present study explored this indexical-linguistic relationship in nonnative speech processing by examining listeners' performance on two tasks: nonnative accent categorization and nonnative speech-in-noise recognition. Results indicated substantial variability across listeners in their performance on both the accent categorization and nonnative speech recognition tasks. Moreover, listeners' accent categorization performance correlated with their nonnative speech-in-noise recognition performance. These results suggest that having more robust indexical representations for nonnative accents may allow listeners to more accurately recognize the linguistic content of nonnative speech.

Children's perception of foreign-accented words.

The acoustic-phonetic realizations of words can vary dramatically depending on a variety of within- and across-talker characteristics such as regional dialect, native language, age, and gender. Robust word learning requires that children are able to recognize words amidst this substantial variability. In the current study, perception of foreign-accented words was assessed in four- to seven-year-old children to test how one form of variability influences word recognition in children. Results demonstrated that children had less accurate word recognition than adults for both native- and foreign-accented words. Both adults and children were less accurate at identifying foreign-accented words compared to native-accented words with children and adults showing similar decrements. For children, age and lexicon size contributed to accurate word recognition.

The influence of talker and foreign-accent variability on spoken word identification.

In spoken word identification and memory tasks, stimulus variability from numerous sources impairs performance. In the current study, the influence of foreign-accent variability on spoken word identification was evaluated in two experiments. Experiment 1 used a between-subjects design to test word identification in noise in single-talker and two multiple-talker conditions: multiple talkers with the same accent and multiple talkers with different accents. Identification performance was highest in the single-talker condition, but there was no difference between the single-accent and multiple-accent conditions. Experiment 2 further explored word recognition for multiple talkers in single-accent versus multiple-accent conditions using a mixed design. A detriment to word recognition was observed in the multiple-accent condition compared to the single-accent condition, but the effect differed across the language backgrounds tested. These results demonstrate that the processing of foreign-accent variation may influence word recognition in ways similar to other sources of variability (e.g., speaking rate or style) in that the inclusion of multiple foreign accents can result in a small but significant performance decrement beyond the multiple-talker effect.

Semantic predictability and adaptation to nonnative speech.

Listeners improve their ability to understand nonnative speech through exposure. The present study examines the role of semantic predictability during adaptation. Listeners were trained on high-predictability, low-predictability, or semantically anomalous sentences. Results demonstrate that trained participants improve their perception of nonnative speech compared to untrained participants. Adaptation is most robust for the types of sentences participants heard during training; however, semantic predictability during exposure did not impact the amount of adaptation overall. Results show advantages in adaptation specific to the type of speech material, a finding similar to the specificity of adaptation previously demonstrated for individual talkers or accents.

Listener characteristics differentially affect self-reported and physiological measures of effort associated with two challenging listening conditions.

Listeners vary in their ability to understand speech in adverse conditions. Differences in both cognitive and linguistic capacities play a role, but increasing evidence suggests that such factors may contribute differentially depending on the listening challenge. Here, we used multilevel modeling to evaluate contributions of individual differences in age, hearing thresholds, vocabulary, selective attention, working memory capacity, personality traits, and noise sensitivity to variability in measures of comprehension and listening effort in two listening conditions. A total of 35 participants completed a battery of cognitive and linguistic tests as well as a spoken story comprehension task using (1) native-accented English speech masked by speech-shaped noise and (2) nonnative accented English speech without masking. Masker levels were adjusted individually to ensure each participant would show (close to) equivalent word recognition performance across the two conditions. Dependent measures included comprehension tests results, self-rated effort, and electrodermal, cardiovascular, and facial electromyographic measures associated with listening effort. Results showed varied patterns of responsivity across different dependent measures as well as across listening conditions. In particular, results suggested that working memory capacity may play a greater role in the comprehension of nonnative accented speech than noise-masked speech, while hearing acuity and personality may have a stronger influence on physiological responses affected by demands of understanding speech in noise. Furthermore, electrodermal measures may be more strongly affected by affective response to noise-related interference while cardiovascular responses may be more strongly affected by demands on working memory and lexical access.

Across-talker effects on non-native listeners' vowel perception in noise.

This study explored how across-talker differences influence non-native vowel perception. American English (AE) and Korean listeners were presented with recordings of 10 AE vowels in /bVd/ context. The stimuli were mixed with noise and presented for identification in a 10-alternative forced-choice task. The two listener groups heard recordings of the vowels produced by 10 talkers at three signal-to-noise ratios. Overall the AE listeners identified the vowels 22% more accurately than the Korean listeners. There was a wide range of identification accuracy scores across talkers for both AE and Korean listeners. At each signal-to-noise ratio, the across-talker intelligibility scores were highly correlated for AE and Korean listeners. Acoustic analysis was conducted for 2 vowel pairs that exhibited variable accuracy across talkers for Korean listeners but high identification accuracy for AE listeners. Results demonstrated that Korean listeners' error patterns for these four vowels were strongly influenced by variability in vowel production that was within the normal range for AE talkers. These results suggest that non-native listeners are strongly influenced by across-talker variability perhaps because of the difficulty they have forming native-like vowel categories.

Perceptual Evaluation of Speech Naturalness in Speakers of Varying Gender Identities.

Purpose The purpose of this study was to investigate how speech naturalness relates to masculinity-femininity and gender identification (accuracy and reaction time) for cisgender male and female speakers as well as transmasculine and transfeminine speakers. Method Stimuli included spontaneous speech samples from 20 speakers who are transgender (10 transmasculine and 10 transfeminine) and 20 speakers who are cisgender (10 male and 10 female). Fifty-two listeners completed three tasks: a two-alternative forced-choice gender identification task, a speech naturalness rating task, and a masculinity/femininity rating task. Results Transfeminine and transmasculine speakers were rated as significantly less natural sounding than cisgender speakers. Speakers rated as less natural took longer to identify and were identified less accurately in the gender identification task; furthermore, they were rated as less prototypically masculine/feminine. Conclusions Perceptual speech naturalness for both transfeminine and transmasculine speakers is strongly associated with gender cues in spontaneous speech. Training to align a speaker's voice with their gender identity may concurrently improve perceptual speech naturalness. Supplemental Material https://doi.org/10.23641/asha.12543158.

Perceptual adaptation and intelligibility of multiple talkers for two types of degraded speech.

Talker intelligibility and perceptual adaptation under cochlear implant (CI)-simulation and speech in multi-talker babble were compared. The stimuli consisted of 100 sentences produced by 20 native English talkers. The sentences were processed to simulate listening with an eight-channel CI or were mixed with multi-talker babble. Stimuli were presented to 400 listeners in a sentence transcription task (200 listeners in each condition). Perceptual adaptation was measured for each talker by comparing intelligibility in the first 20 sentences of the experiment to intelligibility in the last 20 sentences. Perceptual adaptation patterns were also compared across the two degradation conditions by comparing performance in blocks of ten sentences. The most intelligible talkers under CI-simulation also tended to be the most intelligible talkers in multi-talker babble. Furthermore, listeners demonstrated a greater degree of perceptual adaptation in the CI-simulation condition compared to the multi-talker babble condition although the extent of adaptation varied widely across talkers. Listeners reached asymptote later in the experiment in the CI-simulation condition compared with the multi-talker babble condition. Overall, these two forms of degradation did not differ in their effect on talker intelligibility, although they did result in differences in the amount and time-course of perceptual adaptation.

Sentence Context Facilitation for Children's and Adults' Recognition of Native- and Nonnative-Accented Speech.

Purpose Supportive semantic and syntactic information can increase children's and adults' word recognition accuracy in adverse listening conditions. However, there are inconsistent findings regarding how a talker's accent or dialect modulates these context effects. Here, we compare children's and adults' abilities to capitalize on sentence context to overcome misleading acoustic-phonetic cues in nonnative-accented speech. Method Monolingual American English-speaking 5- to 7-year-old children ( n = 90) and 18- to 35-year-old adults ( n = 30) were presented with full sentences or the excised final word from each of the sentences and repeated what they heard. Participants were randomly assigned to 1 of 2 conditions: native-accented (Midland American English) or nonnative-accented (Spanish- and Japanese-accented English) speech. Participants also completed the NIH Toolbox Picture Vocabulary Test. Results Children and adults benefited from sentence context for both native- and nonnative-accent talkers, but the benefit was greater for nonnative than native talkers. Furthermore, adults showed a greater context benefit than children for nonnative talkers, but the 2 age groups showed a similar benefit for native talkers. Children's age and vocabulary scores both correlated with context benefit. Conclusions The cognitive-linguistic development that occurs between the early school-age years and adulthood may increase listeners' abilities to capitalize on top-down cues for lexical identification with nonnative-accented speech. These results have implications for the perception of speech with source degradation, including speech sound disorders, hearing loss, or signal processing that does not faithfully represent the original signal.