Proactive language control is thought to regulate the interference from the nontarget language in bilingual contexts in a sustained way. This study examined the persistence of proactive control in cued picture naming. Participants first named pictures in L1 (German) and L2 (English) in pure blocks, then in mixed language blocks and finally again in pure blocks. In mixed blocks, there were language switch costs, and L1 responses were generally slower than L2 responses (“L1 slowing”). Critically, L1 remained slower than L2 even in postmixing single-language blocks. This persisting L1 slowing suggests overshooting control that downregulates lexical access to L1 representations in a sustained manner. Yet, this persistence of L1 slowing was found only in the first single-language block after the mixed language blocks and no longer in the second postmixing block, suggesting that proactive control has inertia but dissipates over time.
