Mandarin Chinese is typologically unusual among the world’s languages in having flexible word order despite a near absence of inflectional morphology. These features of Mandarin challenge conventional linguistic notions such as subject and object and the divide between syntax and semantics. In the present study, we tested monolingual processing of argument structure in Mandarin verb-final sentences, where word order alone is not a reliable cue. We collected participants’ responses to a forced agent-assignment task while measuring their electroencephalography data to capture real-time processing throughout each sentence. We found that sentence interpretation was not informed by word order in the absence of other cues, and while the coverbs BA and BEI were strong signals for agent selection, comprehension was a result of multiple cues. These results challenge previous reports of a linear ranking of cue strength. Event-related potentials showed that BA and BEI impacted participants’ processing even before the verb was read and that role reversal anomalies elicited an N400 effect without a subsequent semantic P600. This study demonstrates that Mandarin sentence comprehension requires online interaction among cues in a language-specific manner, consistent with models that predict crosslinguistic differences in core sentence processing mechanisms.

Since the early 2000s, neurocognitive research on second language (L2) acquisition has been controversial as to how plastic the human brain is after puberty. Recent studies have extended this debate to first language loss (L1 attrition). This article gives an overview of the first event‐related brain potential (ERP) studies on L1 attrition and L2 learning and discusses their implications for our understanding of the bilingual brain. We will address the highly controversial question of whether L1 morphosyntax is subject to attrition in adult migrants. One previous ERP study on grammatical gender in German migrants failed to find such effects. However, ERP work on grammatical structures in English‐dominant Italian attriters demonstrated that they perceived a grammatical sentence in their L1 as ungrammatical if it violated the L2 grammar. These data suggest that the adult brain remains plastic for both L2 and L1.

The extent to which non-native speakers are sensitive to morphological structure during language processing remains a matter of debate. The present study used a masked-priming lexical decision task with simultaneous electroencephalographic (EEG) recording to investigate whether native and non-native speakers of French yield similar or different behavioral and brain-level responses to inflected verbs. The results from reaction time and EEG analyses indicate that both native and non-native French speakers were indeed sensitive to morphological structure, and that this sensitivity cannot be explained simply by the presence of orthographic or semantic overlap between prime and target. Moreover, sensitivity to morphological structure in non-native speakers was not influenced by proficiency (as reflected by the N400); lower-level learners show similar sensitivity at the word level as very advanced learners. These results demonstrate that native-like processing of inflectional morphology is possible in adult learners, even at lower levels of proficiency, which runs counter to proposals suggesting that native-like processing of inflection is beyond non-native speakers' reach.