Interlingua Developed and Utilized in Real Multilingual MT Product Systems

This paper describes characteristics of an interlingua we have developed. It contains a large lexicon and has been tested on actual MT systems in the translation of large volumes of actual documents. The main characteristics of the interlingua are as follows: (1) Conceptual primitives, elements of the interlingua, can be linked to any parts of speech in English or Japanese. (2) Positions of the top node on the interlingua correspond to differences in syntactic structures. (3) Two or more conceptual graphs can be used for expressing the same concept, and can be converted to another by conceptual transformation rules which are independent of any specific language. (4) Conceptual primitives are divided into two classes; (a) functional conceptual primitives, which are finite and manageable and constitute, along with rules for interpreting conceptual graphs, the grammar of the interlingua, and (b) general conceptual primitives, which correspond to specific words in actual languages and which, depending on the direction of translation, may or may not be used. Our commercial MT products using the interlingua produce results of roughly the same or higher quality than systems using the syntactic transfer method, which fact indicates the feasibility of the interlingua approach.