Neural evidence for encoding communicative functions in speech across linguistic forms with varying iconicity

This study investigates how communicative functions expressed in different prosodies affect the time course of neural responses underlying speech production. In the electroencephalography (EEG)-based picture description task, participants produced Mandarin sentences to describe or complain about events, using onomatopoeias or verbs. Communicative functions affected N1 and P2 time-locked to picture onset in sentences with verbs. The ERP differences in 267–331 ms between communicative functions were present in both the verb and onomatopoeia conditions, but in opposite directions. The effect of communicative functions was manifested in ERP differences 600 ms preceding speech onset, and also in vocal and prosodic features. In sum, for verbs with low iconicity, communicative function had a downstream impact from the early conceptual preparation to the later form encoding processes. These results extend current speech production models by specifying different neurocognitive mechanisms of processing communicative functions in high versus low iconic words during spoken sentence production.