These topic models were originally applied to monolingual data; however, various recent studies have proposed the use of probabilistic topic models in multilingual set-  Most multilingual topic models, including bilingual LDA (BiLDA) (Mimno et al., 2009;Ni et al., 2009), model a document-aligned comparable corpus, such as a collection of Wikipedia articles, where aligned documents are topically similar but are not direct translations 2 .
these models assume that the documents in each tuple share the same topic distribution and that each cross-lingual topic has a language-specific word distribution.