4. The method of claim 3 , wherein the one or more words are obtained as a bag-of-words representation of the query.
3. The method of claim 1 , further comprising: transforming the documents into other phonetic representations; and processing the other phonetic representations to obtain other lower-dimension representations of the documents, the natural language processing operation comprising: mapping the lower-dimension representation of the query and the other lower-dimension representations of the documents into a semantic space; and determining the similarity measures based at least on relative distances between the lower-dimension representation of the query and other lower-dimension representations of the documents in the semantic space.