Entropy and Redundancy of Japanese Lexical and Syntactic Compound Verbs

The present study investigated Japanese lexical and syntactic compound verbs (V1þV2) using Shannon’s concept of entropy and redundancy calculated using corpora from the Mainichi Newspaper and a collection of selected novels. Comparing combinations of a V2 verb with various V1 verbs, syntactic compounds were higher in entropy than lexical ones while neither differed in redundancy. This result suggests that V2 verbs of syntactic compounds are likely to combine with a wider range of V1 verbs than those of lexical compounds. Two exceptional V2 verbs, komu and ageru, both of which create lexical compounds, showed a wide variety of combinations with V1 and therefore act like prefixes in English. Comparing V2 verbs in the two corpora, the V2 eru, which adds the meaning of ‘‘possibility’’ to a V1, functions like the auxiliary verb ‘‘can’’ in English and seems to be a favored expression in newspapers. In contrast, the V2 komu, adds the meaning of ‘‘internal movement’’ similar to the preposition ‘‘into’’ in English and appears to be preferred in the novels to enrich the expression of lexical compounds. In general, both lexical and syntactic compounds were used similarly in both corpora.