Language switching between sentences in reading: Exogenous and endogenous effects on eye movements and comprehension

The present study explored the influence of language switching on both comprehension (utilizing a picture-sentence matching procedure) and word-level processing (utilizing eye movement registration) in reading simple German and English sentences. Language sequence was unpredictable and contained language switches (subsequent sentence in a different language) and language repetitions (subsequent sentence in the same language). The results revealed a substantial decrease of comprehension following language switches (with greater switch costs in L1 than in L2), likely indicating relatively long-lasting, endogenous inhibition processes affecting higher-level text integration. In contrast, there were comparatively minor and transient effects on eye movements (in terms of altered skipping probabilities and gaze durations) that were restricted to the initial words within a sentence, presumably representing short-lasting exogenous (stimulus-driven) activation effects after language switches (with greater switch costs in L2 than in L1). Overall, the results are in line with predictions from recent interactive-activation frameworks of bilingual language processing.