Input language and structural similarity: Competing factors in early third language acquisition

Aims and objectives: This paper presents two artificial language learning experiments that each investigated factors affecting crosslinguistic influence (CLI) in third language acquisition by Norwegian–English sequential bilinguals. Methodology: We tested the effect of two factors: the structural similarity between pre-existing languages and the target language, and the input language, that is, the language used to instruct the participants during the experiment. Data and analysis: We fitted the data to mixed-effects logistic regression models in a step-wise step-up forward elimination procedure. Findings and conclusions: In Experiment 1, we found an effect of structural similarity. In Experiment 2, the results indicated that the effects of input language could override similarity. Originality: While the effect of structural similarity on CLI is well-attested, the effect of the input language is less explored. The latter factor is often mentioned in literature discussing CLI in third language acquisition, but is rarely explored empirically. Significance/implications: The findings indicated that contextual factors may exert a greater influence than previously recognized in existing models of third language acquisition.