To build a suitable data set 2 for fluency detection, we first identified 1000 Twitter users who, according to the Twitter LID system, have tweeted in Russian and at least one additional language.
social media platforms like Twitter produce data sets in which individual documents are extremely short, and language use is idiosyncratic: LID performance on such data is dramatically lower than on traditional corpora (Bergsma et al., 2012;Carter et al., 2013).