The nature and processing of semantic illusions (SI; when speakers fail to notice an anomalous word in a sentence that is contextually perfectly aligned with world knowledge) have been largely studied during first language comprehension. Although this issue is not free of controversy, findings sustain The Node Structure Theory, according to which SI is a phonological and/or semantic priming effect which occurs due to phonological and/or semantic links existing between the correct and the anomalous word. However, the question as to whether the same underlying mechanisms can be found in bilinguals and whether the effect is modulated by age of language acquisition (AoA) and language dominance remains unexplored. The aim of this study was to examine this issue on sequential European Portuguese-German bilinguals (and their respective control groups) using a self-paced reading paradigm. The sentences’ language, AoA (early vs. late), and type of target word used (correct vs. anomalous) were manipulated. Results showed the occurrence of SI, independently of language and AoA. Therefore, findings suggest that SI occur due to a semantic overlap between critical words and are similarly processed in L1 and L2.

Research among bilinguals suggests a foreign language effect for various tasks requiring a more systematic processing style. For instance, bilinguals seem less prone to heuristic reasoning when solving problem statements in their foreign (FL) as opposed to their native (NL) language. The present study aimed to determine whether such an effect might also be observed in the detection of semantic anomalies. Participants were presented NL and FL questions with and without anomalies while their eye movements were recorded. Overall, they failed to detect the anomaly in more than half of the trials. Furthermore, more illusions occurred for questions presented in the FL, indicating an FL disadvantage. Additionally, eye movement analyses suggested that reading patterns for anomalies are predominantly similar across languages. Our results therefore substantiate theories suggesting that FL use induces cognitive load, causing increased susceptibility to illusions due to partial semantic processing.