Two-level alignment by words and phrases based on syntactic information

Abstract

As a part of work on alignment of the English and Korean parallel corpus, this paper presents a statistical translation model incorporating linguistic knowledge of syntactic and phrasal information for better translations. For this, we propose three models: First, we incorporate syntactic information such as part of speech into the word-based lexical alignment. Based on this model, we propose the second model which finds phrasal correspondence in the parallel corpus. Phrasal mapping through chunk-based shallow parsing enables to settle mismatch of meaningful units in the two languages. Lastly, we develop a two-level alignment model by combining these two models in order to construct both the word and phrase-based translation model. Model parameters are automatically estimated from a set of bilingual sentence pairs by applying the EM algorithm. Experiments show that the structural relationship helps construct a better translation model for structurally different languages like Korean and English. © Springer-Verlag 2004.