Errors in foreign language acquisition as a multifaceted phenomenon: the case of Russian aspect

We study factors influencing aspectual errors in written texts of advanced learners of Russian with dominant English. Our study is based on the data from the Russian Learner Corpus, as well as a mini-corpus collected from a group of advanced Russian learners who are native speakers of English. Our findings suggest that the incidence, direction, and type of aspectual errors depend on the level of language mastery. On lower levels, there are more perfective-to-imperfective substitutions ((sic) 'I finally did.IPF my homework' instead of (sic) 'I finally did.PF my homework'), possibly due to greater morphological simplicity of erroneous imperfective forms, as well as their earlier instruction and acquisition. However, on higher levels of language mastery, the number of imperfective-to-perfective substitutions increases ((sic) 'I don't want to buy.PF him a present' instead of (sic) 'I don't want to buy.IPF him a present'). Perfective tends to replace imperfective, irrespectively of the morphological complexity, in cases when the required use of imperfective is driven by grammatical rules rather than the semantics of the form, e.g. in iterative or negative constructions. Possibly, it happens because learners are guided by the aspectual semantics (lexical aspect) and disregard the grammatical rules when they contradict it (morphological aspect). Additionally, it appears that both perfective-to-imperfective and imperfective-to-perfective substitutions are context-dependent. Both tend to happen less frequently in finite, factual past contexts, and more frequently in non-finite, non-factual contexts where aspectual oppositions are mitigated.