1. A method performed by a computing device, the method comprising: obtaining a query comprising one or more words from a vocabulary having a first dimension; transforming the one or more words of the query into a phonetic representation of the one or more words; processing the phonetic representation to obtain a lower-dimension representation comprising a plurality of n-grams in an n-gram space having a second dimension that is smaller than the first dimension; performing a natural language processing operation on the lower-dimension representation, the natural language processing operation comprising determining similarity measures reflecting similarity of the one or more words of the query to a plurality of documents; based at least on the similarity measures, selecting a subset of the documents that are relevant to the query; and outputting the selected subset of documents in response to the query.