The encoder-decoder abstraction makes it conceptually feasible to build a system that maps any source sentence in any language to a vector representation, and then decodes this representation into any target language.
various approaches have been proposed to extend this abstraction for multilingual MT (Luong et al., 2016;Dong et al., 2015;Johnson et al., 2017;Ha et al., 2016;Firat et al., 2016a).