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Producing word-initial /s/-stop clusters can be a challenge for English-speaking pre-schoolers. For children with hearing loss (HL), fricatives can be also difficult to perceive, raising questions about their production and representation of /s/-stop clusters. The goal of this study was therefore to determine if pre-schoolers with HL can produce and represent the /s/ in word-initial /s/-stop clusters, and to compare this to their normal hearing (NH) peers. Based on both acoustic and perceptual analysis, we found that children with HL had little /s/-omission, suggesting that their phonological representation of these clusters closely aligns with that of their NH peers.

Purpose: Children with hearing loss (HL), including those with hearing aids (HAs) and cochlear implants (CIs), often have difficulties contrasting words like " b each " versus " p each " and " do g " versus " do ck " due to challenges producing systematic voicing contrasts. Even when acoustic contrasts are present, these may not be perceived as such by others. This can cause miscommunication, leading to poor self-esteem and social isolation. Acoustic evidence is therefore needed to determine if these children have established distinct voicing categories before entering school and if misperceptions are due to a lack of phonological representations or due to a still-maturing implementation system. The findings should help inform more effective early intervention., Method: Participants included 14 children with HL (eight HA users, five CI users, and one bimodal) and 20 with normal hearing, all English-speaking preschoolers. In an elicited imitation task, they produced consonant-vowel-consonant minimal pair words that contrasted voicing in word-initial (onset) or word-final (coda) position at all three places of articulation (PoAs)., Results: Overall, children with HL showed acoustically distinct voicing categories for both onsets and codas at all three PoAs. Contrasts were less systematic for codas than for onsets, as also confirmed by adults' perceptual ratings., Conclusions: Preschoolers with HL produce acoustic differences for voiced versus voiceless onsets and codas, indicating distinct phonological representations for both. Nonetheless, codas were less accurately perceived by adult raters, especially when produced by CI users. This suggests a protracted development of the phonetic implementation of codas, where CI users, in particular, may benefit from targeted intervention.

While voicing contrasts in word-onset position are acquired relatively early, much less is known about how and when they are acquired in word-coda position, where accurate production of these contrasts is also critical for distinguishing words (e.g., dog vs. dock). This study examined how the acoustic cues to coda voicing contrasts are realized in the speech of 4-year-old Australian English-speaking children. The results showed that children used similar acoustic cues to those of adults, including longer vowel duration and more frequent voice bar for voiced stops, and longer closure and burst durations for voiceless stops along with more frequent irregular pitch periods. This suggests that 4-year-olds have acquired productive use of the acoustic cues to coda voicing contrasts, though implementations are not yet fully adult-like. The findings have implications for understanding the development of phonological contrasts in populations for whom these may be challenging, such as children with hearing loss.

Voicing contrasts are lexically important for differentiating words in many languages (e.g., "bear" vs "pear"). Temporal differences in the voice onset time (VOT) and closure duration (CD) contribute to the voicing contrast in word-onset position. However, little is known about the acoustic realization of these voicing contrasts in Australian English-speaking children. This is essential for understanding the challenges faced by those with language delay. Therefore, the present study examined the VOT and CD values for word-initial stops as produced by 20 Australian English-speaking 4-5-year-olds. As anticipated, these children produced a systematic distinction between voiced and voiceless stops at all places of articulation (PoAs). However, although the children's VOT values for voiced stops were similar to those of adults, their VOTs for voiceless stops were longer. Like adults, the children also had different CD values for voiced and voiceless categories; however, these were systematically longer than those of adults. Even after adjusting for temporal differences by computing proportional ratios for the VOT and CD, children's voicing contrasts were not yet adultlike. These results suggest that children of this age are still developing appropriate timing and articulatory adjustments for voicing contrasts in the word-initial position.