What makes some words harder to learn than others in a second language? Although some robust factors have been identified based on small scale experimental studies, many relevant factors are difficult to study in such experiments due to the amount of data necessary to test them. Here, we investigate what factors affect the ease of learning of a word in a second language using a large data set of users learning English as a second language through the Duolingo mobile app. In a regression analysis, we test and confirm the well-studied effect of cognate status on word learning accuracy. Furthermore, we find significant effects for both cross-linguistic semantic alignment and English semantic density, two novel predictors derived from large scale distributional models of lexical semantics. Finally, we provide data on several other psycholinguistically plausible word level predictors. We conclude with a discussion of the limits, benefits and future research potential of using big data for investigating second language learning.

Bilinguals are purported to be more creative than monolinguals, but the mechanism for this bilingual advantage is stillunresolved, with several different accounts proposed. Others have challenged the existence of bilingual advantages ingeneral. We examine existence as well as hypothesized semantic network difference based mechanisms for the relationshipbetween bilingualism and creativity here by measuring creativity and fluency for monolinguals and bilinguals. The fluencymeasure allowed us to analyze the structure of individuals semantic networks (average shortest path length, clusteringcoefficient, and modularity). We found no differences in creativity between monolingual and bilingual participants, with aBayesian test showing substantial evidence for the null hypothesis. We did find that aspects of semantic network structurepredicted creativity. These findings suggest that, contrary to previous work, the bilingual advantage does not exist in therealm of creativity.