We make sense of objects and events around us by classifying them into identifiable categories. The extent to which language affects this process has been the focus of a long-standing debate: Do different languages cause their speakers to behave differently? Here, we show that fluent German-English bilinguals categorize motion events according to the grammatical constraints of the language in which they operate. First, as predicted from cross-linguistic differences in motion encoding, participants functioning in a German testing context prefer to match events on the basis of motion completion to a greater extent than participants in an English context. Second, when participants suffer verbal interference in English, their categorization behavior is congruent with that predicted for German and when we switch the language of interference to German, their categorization becomes congruent with that predicted for English. These findings show that language effects on cognition are context-bound and transient, revealing unprecedented levels of malleability in human cognition.

Can recent second language (L2) exposure affect what we judge to be similar events? Using a priming paradigm, we manipulated whether native Swedish adult learners of L2 Spanish were primed to use path or manner during L2 descriptions of scenes depicting caused motion events (encoding phase). Subsequently, participants engaged in a nonverbal task, arranging events on the screen according to similarity (test phase). Path versus manner priming affected how participants judged event similarity during the test phase. The effects we find support the hypotheses that (a) speakers create or select ad hoc conceptual categories that are based on linguistic knowledge to carry out nonverbal tasks, and that (b) short-term, recent L2 experience can affect this ad hoc process. These findings further suggest that cognition can flexibly draw on linguistic categories that have been implicitly highlighted during recent exposure.

Does the way we talk about events correspond to how we conceptualize them? Three experiments (N = 135) examined how Spanish and Swedish native speakers judge event similarity in the domain of caused motion (‘He rolled the tyre into the barn’). Spanish and Swedish motion descriptions regularly encode path (‘into’), but differ in how systematically they include manner information (‘roll’). We designed a similarity arrangement task which allowed participants to give varying weights to different dimensions when gauging event similarity. The three experiments progressively reduced the likelihood that speakers were using language to solve the task. We found that, as long as the use of language was possible (Experiments 1 and 2), Swedish speakers were more likely than Spanish speakers to base their similarity arrangements on object manner (rolling/sliding). However, when recruitment of language was hindered through verbal interference, cross-linguistic differences disappeared (Experiment 3). A compound analysis of all experiments further showed that (i) cross-linguistic differences were played out against a backdrop of commonly represented event components, and (ii) describing vs. not describing the events did not augment cross-linguistic differences, but instead had similar effects across languages. We interpret these findings as suggesting a dynamic role of language in event conceptualization.

Native language (L1) processing draws on implicit expectations. An open question is whether non-native learners of a second language (L2) similarly draw on expectations, and whether these expectations are based on learners’ L1 or L2 knowledge. We approach this question by studying inverse preference effects on lexical encoding. L1 and L2 speakers of Spanish described motion events, while they were either primed to express path, manner, or neither. In line with other work, we find that L1 speakers adapted more strongly after primes that are unexpected in their L1. For L2 speakers, adaptation depended on their L2 proficiency: The least proficient speakers exhibited the inverse preference effect on adaptation based on what was unexpected in their L1; but the more proficient speakers were, the more they exhibited inverse preference effects based on what was unexpected in the L2. We discuss implications for L1 transfer and L2 acquisition.