Recovering Word Forms by Context for Morphologically Rich Languages

In this work, we focus on “sentence-level unlemmatization,” the task of generating a grammatical sentence given a lemmatized one; this task is usually easy to do for humans but may present problems for machine learning models. We treat this setting as a machine translation problem and, as a first try, apply a sequence-to-sequence model to the texts of Russian Wikipedia articles, evaluate the effect of the different training sets sizes quantitatively and achieve the BLUE score of 67, 3 using the largest training set available. We discuss preliminary results and flaws of traditional machine translation evaluation methods for this task and suggest directions for future research.