17. An apparatus that generates and selects superwords, comprising: a database of observed sequences of words, symbols and/or sounds, the database having a perplexity value based on a language model; and a superword selector that generates candidate phrases from the database, the selector incorporating one of the candidate phrases from the database into the language model, the selector further analyzing how the perplexity value of the database, which is based on the language model, is affected by the incorporated candidate phrase and determining whether the candidate phrase is a superword based on the analysis.
20. The apparatus of claim 17, further comprising: a recognizer that uses the database to recognize any of the superwords contained in a user's input.