Voiced Implosive Acquisition: Acoustic Analyses of /ɓ/ and /ɗ/ as Produced by Shimaore-Speaking Children 3;0 to 7;1 on Mayotte Island

While relatively rare, implosives can be observed in numerous African languages such as Fulfulde, isiXhosa, and isiZulu. Research on the acquisition of implosives remains limited; however, the few existing studies suggest that these sounds are typically acquired by around age 3;0. Despite these findings, the developmental processes underlying this class of sounds in children are still not well understood. Notably, most studies look at the bilabial implosive /ɓ/, and tend to emphasize categorical acquisition, with relatively little attention given to the acoustic characteristics involved in implosive development. To address this lacuna, this study investigates implosive acquisition in Shimaore, a Bantu language spoken on the French island of Mayotte. Cross-sectional methodologies are used to examine the way Shimaore-French bilingual children produce /ɓ/ and /ɗ/ during a nonword repetition task. Participants were 53 children aged 3;0 to 7;1. Sounds were analyzed using acoustic features, including Voice Onset Time, f0, H1*–H2*, and Cepstral Peak Performance. The results indicated that while children produce implosives at 3;0, they also frequently substitute these sounds with nasals, voiceless stops, and approximants. Nonetheless, substitutions decrease with age. Acoustic analyses demonstrate that, over time, children’s production of implosives increasingly resembles those of adult speakers. These findings are consistent with contemporary phonological theory on language acquisition, particularly the A-Map model, which focuses on constraints related to both accuracy and precision.