1. A method comprising: receiving, from an automatic speech recognition system, a word lattice based on a speech query; composing a triple comprising a query word from the speech query, an indexed document, and a weight; generating an N-best path through the word lattice based on the triple; re-ranking automatic speech recognition output based on the N-best path, to yield re-ranked automatic speech recognition output; and returning search results to the speech query based on the re-ranked automatic speech recognition output.