30. A method of matching candidate words in an utterance to items in catalog entries, the method including: accessing a phrase dictionary representing catalog entries for the items, wherein all of the phrases used to select the items are represented in the phrase dictionary; receiving candidate phoneme sequences tentatively recognized from the utterance, with confidence scores; traversing parts of the phrase dictionary, in parallel using multiple processors, locating candidate phrases that match sequences within the utterance of non-overlapping candidate phonemes; calculating phrase confidence scores for the candidate phrases; and reporting at least a subset of the candidate phrase and respective candidate phrase scores for further processing.
32. The method of claim 30 , wherein the phrase dictionary is represented by phase graphs with optional edges that indicate words subject to deletion.