Sentence-Final Particles in Mandarin Child-Directed Speech: A Corpus-Based Analysis of Frequency and Prosody

Purpose: Sentence-final particles (SFPs) are an important word class in Mandarin that mark utterance type and express emotions. This study examined SFP use in Mandarin child-directed speech (CDS) and adult-directed speech (ADS), focusing on SFPs’ frequency and associations with utterance-level prosody. Method: We analyzed a corpus of ADS and CDS produced by forty Mandarin-speaking mothers during a storytelling task. Utterances (N = 6227) were coded for SFP presence and utterance type (e.g., declarative, interrogative). We used linear mixed-effects models to compare the overall SFP frequency and the utterance-level prosody between ADS and CDS. A mediation analysis tested whether the frequency of interrogative utterances mediated the effect of register on SFP frequency. KL divergences were calculated to examine whether the whole distributions of individual SFPs differed across registers. Results: SFPs occurred more frequently in CDS than in ADS, but this difference was no longer significant after controlling for utterance type. Mediation analysis revealed that the higher frequency of SFPs in CDS was mediated by the higher frequency of interrogative utterances. The use of individual SFPs also exhibited significant differences across registers. In CDS, utterances with SFPs showed faster articulation rate than utterances without SFPs, whereas this pattern was not observed in ADS. Conclusions: Mandarin-speaking mothers used SFPs differently across ADS and CDS. The higher SFP frequency in CDS primarily reflected differences in utterance type distribution. In CDS, SFPs co-occurred with a distinct prosodic pattern characterized by a faster articulation rate, which may facilitate children’s understanding of communicative intent and emotions in caregivers’ speech.