Abstract
This paper carries out a quantitative analysis of morpholexical difference between machine-translated Japanese sentences and human-translated ones, both of which are obtained from English sentences selected randomly from news articles. The analysis gives the following results.(1) A tendency to translate one English sentence into multiple Japanese sentences is less observed in machine translation than in human translation.(2) Significant difference exists in the distribution of the sentence length between machine-and human-translated sentences.(3) Significant difference in the distribution of the adverbial form and the attributive form of verbs and adjectives intimates that machine-translated sentences have more complex syntactic structure than human-translated ones do.(4) No significant difference exists in the distribution between verbs, adjectives and nouns.
A further investigation on verbs and nouns reveals what kind of technical challenges must be solved to improve the quality of machine translation up to the extent of human translation.
