16. The system of claim 11 , wherein training the lexical association model further comprises finding associated answer words for the query word and building an expansion set for the query word, wherein the expansion set comprises an answer word.
16. The system of claim 11 , wherein training the lexical association model further comprises finding associated answer words for the query word and building an expansion set for the query word, wherein the expansion set comprises an answer word. 17. The system of claim 16 , wherein expanding the query words further comprises finding a question phrase that the question begins with, locating nouns in the question phrase, and replacing the question phrase with associated named entity tags and the nouns appearing in the question phrase.