15. A computer system comprising: means for storing an acoustic description of each of a plurality of vocabulary words; means for receiving an acoustic description of one or more utterances to be recognized; recognition means for comparing the acoustic descriptions of utterances to be recognized against the acoustic descriptions of a recognition vocabulary comprised of one or more of said vocabulary words to select which of the words in said recognitino vocabulary most probably corresponds to said one or more utterances; a data structure representing one or more words, said data structure being other than a list of said vocabulary words; means for using said data structure for a purpose independent both of indicating which words are vocabulary words and of indicating the probability that individual vocabulary words will be recognized as corresponding to a given utterance; probability altering means for determining which of said vocabulary words are represented by said data structure and for using that determination to alter the probability that each of said vocabulary words will be selected as corresponding to a given utterance.
15. A computer system comprising: means for storing an acoustic description of each of a plurality of vocabulary words; means for receiving an acoustic description of one or more utterances to be recognized; recognition means for comparing the acoustic descriptions of utterances to be recognized against the acoustic descriptions of a recognition vocabulary comprised of one or more of said vocabulary words to select which of the words in said recognitino vocabulary most probably corresponds to said one or more utterances; a data structure representing one or more words, said data structure being other than a list of said vocabulary words; means for using said data structure for a purpose independent both of indicating which words are vocabulary words and of indicating the probability that individual vocabulary words will be recognized as corresponding to a given utterance; probability altering means for determining which of said vocabulary words are represented by said data structure and for using that determination to alter the probability that each of said vocabulary words will be selected as corresponding to a given utterance. 21. A computer system as described in claim 15 wherein said data structure represents a body of text.