To determine when and how L2 learners start to process L2 words affectively and semantically, we conducted a longitudinal study on their interaction in adult L2 learners. In four test sessions, spanning half a year of L2 learning, we monitored behavioral and ERP learning-related changes for one and the same set of words by means of a primed lexical-decision paradigm with L1 primes and L2 targets. Sensitivity rates, accuracy rates, RTs, and N400 amplitude to L2 words and pseudowords improved significantly across sessions. A semantic priming effect (e.g, prime “driver”facilitating response to target “street”) was found in accuracy rates and RTs when collapsing Sessions 1 to 4, while this effect modulated ERP amplitudes within the first 300 ms of L2 target processing. An overall affective priming effect (e.g., “sweet” facilitating”taste”) was also found in RTs and ERPs (posterior P1). Importantly, the ERPs showed an L2 valence effect across sessions (e.g., positive words were easier to process than neutral words), indicating that L2 learners were sensitive to L2 affective meaning. Semantic and affective priming interacted in the N400 time-window only in Session 4, implying that they affected meaning integration during L2 immersion together. The results suggest that L1 and L2 are initially processed semantically and affectively via relatively separate channels that are more and more linked contingent on L2 exposure.

a b s t r a c tIn a long-lag morphological priming experiment, Dutch (L1)-English (L2) bilinguals were asked to name pictures and read aloud words. A design using non-switch blocks, consisting solely of Dutch stimuli, and switch-blocks, consisting of Dutch primes and targets with intervening English trials, was administered. Target picture naming was facilitated by morphologically related primes in both non-switch and switch blocks with equal magnitude. These results contrast some assumptions of sustained reactive inhibition models. However, models that do not assume bilinguals having to reactively suppress all activation of the non-target language can account for these data.