Many documents in one language are shortened or adapted translations 1 of documents from other (not always the same) languages and this property of Wikipedia together with its size makes it the ideal candidate of a strongly comparable corpus from which parallel sentences can be mined.
depending on the comparability level of the extraction corpus, the quantity of parallel data extracted may range from 0.1% (weakly comparable corpora) to 29% (strongly comparable corpora) of the entire corpus (Ion et al., 2011).