Although morphosyntax has been identifi ed as a major source of diffi culty for adult (nonnative) language learners, most previous studies have examined a limited set of largely affi x-based phenomena. Little is known about word-based morphosyntax in late bilinguals and of how morphosyntax is represented and processed in a nonnative speaker's lexicon. To address these questions, we report results from two behavioral experiments investigating stem variants of strong verbs in German (which encode features such as tense, person, and number) in groups of advanced adult learners as well as native speakers of German. Although the late bilinguals were highly proficient in German, the results of a lexical priming experiment revealed clear native-nonnative differences. We argue that lexical representation and processing relies less on morphosyntactic information in a nonnative than in a native language.

This study addresses the question of how age of acquisition (AoA) affects grammatical processing, specifically with respect to inflectional morphology, in bilinguals. We examined experimental data of more than 100 participants from the Russian/German community in Berlin, all of whom acquired Russian from birth and German at different ages. Using the crossmodal lexical priming technique, we investigated stem allomorphs of German verbs that encode multiple morphosyntactic features. The results revealed a striking AoA modulation of observed priming patterns, indicating efficient access to morphosyntactic features for early AoAs and a gradual decline with increasing AoAs. In addition, we found a discontinuity in the function relating AoA to morphosyntactic feature access, suggesting a sensitive period for the development of morphosyntax.

How do late proficient bilinguals process morphosyntactic and lexical-semantic information in their non-native language (L2)? How is this information represented in the L2 mental lexicon? And what are the neural signatures of L2 morphosyntactic and lexical-semantic processing? We addressed these questions in one behavioral and two ERP priming experiments on inflected German adjectives testing a group of advanced late Russian learners of German in comparison to native speaker (L1) controls. While in the behavioral experiment, the L2 learners performed native-like, the ERP data revealed clear L1/L2 differences with respect to the temporal dynamics of grammatical processing. Specifically, our results show that L2 morphosyntactic processing yielded temporally and spatially extended brain responses relative to L1 processing, indicating that grammatical processing of inflected words in an L2 is more demanding and less automatic than in the L1. However, this group of advanced L2 learners showed native-like lexical-semantic processing.

The aim of this review is to provide a selective overview of priming studies which have employed the event-related brain potential (ERP) technique in order to investigate bilingual language processing. The priming technique can reveal an implicit memory effect in which exposure to one stimulus influences the processing of another stimulus. Behavioral approaches, such as measuring reaction times, may not always be enough for providing a full view on the exact mechanisms and the time-course of language comprehension. Instead, ERPs have a time-resolution of a millisecond and hence, they offer a precise temporal overview of the underlying neural processes involved in language processing. In our review, we summarize experimental research which has combined priming with ERP measurements, thus creating a valuable tool for examining the neurophysiological correlates of language processing in the bilingual brain.

In fusional languages, inflectional affixes may encode multiple morphosyntactic features such as case, number, and gender. To determine how these features are accessed during both native (L1) and non-native (L2) word recognition, the present study compares the results from a masked visual priming experiment testing inflected adjectives of German to those of a previous overt (cross-modal) priming experiment on the same phenomenon. While for the L1 group both experiments produced converging results, a group of highly-proficient Russian L2 learners of German showed native-like modulations of repetition priming effects under overt, but not under masked priming conditions. These results indicate that not only affixes but also their morphosyntactic features are accessible during initial form-based lexical access, albeit only for L1 and not for L2 processing. We argue that this contrast is in line with other findings suggesting that non-native language processing is less influenced by structural information than the L1.