The recent literature[8] shows that the belief "natural languages are not context-free" is not necessarily true, and there is no reason for us to give up the context-freedom of natural languages. We (to not discuss on this matter further, considering the fact that even if natural languages are not context-free, a fairly comprehensive grammar for a subset of natural language suflicient for practical systems can be written in phrase structure. lhtJ.% our main concern is how to cope with the ambiguity of natural languages, and this concern is addressed in the fallowing section. .
