1. A computer implemented method for building a language model for use in a QA system comprising: receiving a question, comprising a definitional question or a factoid, and determining a question focus of the question; querying a source of information with the question focus and obtaining one or more relevant documents; generating a centroid vector based on the question focus and said one or more relevant documents: generating an ordered centroid based on the centroid vector: and utilizing a computer processor that is a component of a computing device to build the language model based on the ordered centroid.