Lexical gaps and idioms in machine translation

A bstract This paper deserihes the treatment of lexical gaps, collocation information and idioms in the English to Portuguese machine translation system PORTUGA. The perspective is strictly bilingual, in the sense that all problems referenced above are considered to behmg to the tranM'cr phase, and not, as in other systems, to analysis or generation. The solution presented invokes a parser fi}r the target language (Portuguese) that analyses, producing the corresponding graph structure, the multiword expression selected as the result of lexieal transfer. This process seems to bring considerable advantage in what readability and ease of bilingual dictionary development is concerned, and to fiirnish maximal flexihility together with minimal storage requirements. Finally, it also provides complete independence between dictionary-rod grammar formalisms. Organization 'lhe general architecture of" the MT system is at first described very briefly, emphasizing the features relevant to the full understanding of the problem at hand. Then tim problem is presented, and a literature survey given. The solution put tbrward is then described. Finally, we fiwnish a detailed example, together with some evaluation results. The structure of the transfer MT system POR.TUGA is illustrated in Figure 1. 'lhe main characteristics of this English to Portuguese transhm)r are: the separation between possible translation (which may be multiple), and best or chosen translation (decided in the "style Iransfer" module). ® Complete independence between English and Portuguese processing. English analysis is performed hy PEG[8]. • Bilingual dictionary being kept to a minimum, only the selection conditions for lexical transfer and contrastive knowledge are stored. It should also be mentioned that all intbrmation in this dictionary is associated with the translations, and not to the English index, as is usual for lexical transfer in MT.