An alternative approach that we follow here is to independently train the embeddings for each language on monolingual corpora, and then learn a linear transformation to map the embeddings from one space into the other by minimizing the distances in a bilingual dictionary, usually in the range of a few thousand entries (Mikolov et al., 2013a;Artetxe et al., 2016).
dictionaries of that size are not readily available for many language pairs, specially those involving less-resourced languages.