A robust temporal map of speech monitoring from planning to articulation

Speakers continuously monitor their own speech to optimize fluent production. However, the precise timing and underlying variables influencing speech monitoring remain insufficiently understood. This study aimed to provide a comprehensive temporal map of monitoring processes ranging from speech planning to articulation. Two closely resembling experiments were conducted, focusing on effects that consistently emerged across both. Participants engaged in a speeded language production task designed to elicit speech errors of either a lexical or articulatory-phonetic origin, while their EEG activity was recorded. On correctly produced utterances, we explored error probability at different levels of processing (lexical and articulatory-phonetic) and we also compared errors with correct trials to capture the potential diversity of response conflict and monitoring processes. Concerning the effects of error probability on correct trials, differences driven by the lexical status of a competing response were observed during initial stages of speech planning, while differences related to articulatory phonetically driven response competition emerged during speech motor preparation. In contrast, errors showed differences with correct utterances in both early and late speech motor preparation and during articulation. Taken together, these findings suggest that (a) response conflict on ultimately correct trials does not persist during articulation; (b) the timecourse of response conflict is restricted to the time window during which a given linguistic level is task relevant (early on for response appropriateness related variables and later for articulation relevant variables); and (c) monitoring during the response seems to be primarily triggered by pre-response monitoring failure.