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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).

Hesitation phenomena in natural speech (e.g., pauses, word repetitions, or phrase repairs) vary as a function of speaker characteristics, with non-native speakers typically hesitating more than native speakers (Gilquin, 2008). Here, we examine whether hesitations can also reflect listeners’ mental effort required to comprehend native and non-native speech. We asked native English listeners to retell stories told by either a native or a non-native speaker and analyzed their hesitations using a 6-category taxonomy: filler vocalizations, filler words, filler nonspeech, self-monitoring, uptalk, and point of view switching. These story-retell behavioral data were obtained after recording their brain responses during listening to the stories using functional near-infrared spectroscopy (fNIRS) and speaker-listener interbrain synchrony technique (hyperscanning). We found a higher hesitation rate for retelling of stories produced by a non-native (11.2%) than a native speaker (7.6%), with significant increase in hesitation frequency for the former. The hesitations corroborated brain responses: Listeners had greater difficulty processing discourse in non-native English and the recruitment of additional executive resources delayed comprehension and memory processes. The analysis of hesitations is a promising approach in measuring speaker-listener communicative effort because hesitations increase as uncertainty of interpretation increases, suggesting greater demands on working memory during lexical and semantic operations.

The development of stop consonant voicing in English-speaking children has been documented as a progressive mastery of phonological contrast, but implementation of voicing within one voicing category has not been systematically examined. This study provides a comprehensive account of structured variability in phonetic realization of /b/ in running speech by 8–12-year-old American children (n = 48) when compared to adults (n = 36). The stop always occurred word-initially, was followed by either a voiced or voiceless coda, and its position varied in a sentence, which created systematic conditions to examine acoustic variability in closure duration (CD) and voicing during the closure (VDC) stemming from phonetic context and prosodic prominence. Children demonstrated command of long-distance anticipatory coarticulation, providing evidence that information about coda voicing is distributed over an entire monosyllabic word and is available in the onset stop. They also manifested covariation of cues to stop voicing and command of prosodic variation, despite greater random variability, greater CD, reduced VDC, and exaggerated execution of sentential focus when compared to adults. Controlling for regional variation, dialect was a significant predictor for adults but not for children, who no longer adhered to the marked local variants in their implementation of stop voicing.

Research shows that gender in the voices of prepubescent children can be identified relatively well, despite the absence of reliable anatomical differences related to their vocal tract morphology. This implies that information about differences in girls’ and boys’ voices also resides in behavioral and cultural aspects of speech and not exclusively in the acoustic cues corresponding to anatomical differences. The observed improved gender identification (gID) for sentences over syllables suggests that longer stretches of speech provide listeners with a richer acoustic basis for their decisions. Here, we introduce two additional factors that may affect gID: speaking style and children’s dialect. Children (n = 92) ages 8;0–12;4 years, boys (n = 45) and girls (n = 47) from Ohio, Wisconsin, and North Carolina produced isolated syllables, read sentences, and spontaneous utterances. Listeners were young adults from Ohio. Expectedly, gID accuracy for sentences/utterances was greater (66%) than for syllables (55%), and for older than younger children. Dialect was a significant predictor for younger (but not older) children, with the highest gID for Ohio. Overall, spontaneous utterances did not provide more gender information than read sentences except for older children from North Carolina, suggesting that cultural traits in conversational dynamics can also be useful to listeners in gID.

In English, the strongest acoustic cues to preserving the voicing contrast in coda stops are in the preceding vowel: a voiced coda is associated with a longer vowel and a voiceless coda with a shorter vowel. Our recent work (Jacewicz et al ., 2021) examining structured variability in stop voicing implementation in female productions showed that the cues to stop coda voicing extended to the syllable initial stop. In running speech, the /b/-closure in “bad” was shorter when coda was voiced, and it was longer when coda was voiceless (“bat”). Here, we test the hypothesis that voicing contrast cueing the “bad-bat” distinction is reinforced syllable-wide and involves specific long-distance timing relationships between closures of both stops, the extent of their closure voicing, vowel duration, and positive VOT. The current dataset consists of 2610 productions by 45 adult males, who are also diversified by dialect. Preliminary analyses confirmed that segmental voicing information is distributed over long domains (here, a monosyllabic word) and that cues to coda voicing are available in the syllable onset. These findings imply that temporal relationships among acoustic phonetic detail cueing lexical distinctions can potentially enhance the perceptual dimensions of perceived syllable- or word-wide voicelessness and voicing.