Because of globalization, it is becoming
more and more common to use multiple languages in a single utterance, also called codeswitching. This results in special linguistic
structures and, therefore, poses many challenges for Natural Language Processing. Existing models for language identification in
code-switched data are all supervised, requiring annotated training data which is only available for a limited number of language pairs.
In this paper, we explore semi-supervised approaches, that exploit out-of-domain monolingual training data. We experiment with
word uni-grams, word n-grams, character ngrams, Viterbi Decoding, Latent Dirichlet Allocation, Support Vector Machine and Logistic Regression. The Viterbi model was
the best semi-supervised model, scoring a
weighted F1 score of 92.23%, whereas a fully
supervised state-of-the-art BERT-based model
scored 98.43%.