7. The method of claim 2 wherein the step of ranking each of the plurality of documents based on the spoken query includes representing the spoken query by a vector of weighted N-grams.
7. The method of claim 2 wherein the step of ranking each of the plurality of documents based on the spoken query includes representing the spoken query by a vector of weighted N-grams. 8. The method of claim 7 wherein the step of ranking each of the plurality of documents based on the spoken query further includes calculating a posteriori probabilities for each term in the spoken query and using the a posteriori or probabilities as weights.