16. A method of speech recognition, comprising providing state identifiers which identify states corresponding to nodes or groups of adjacent nodes in a lexical tree, the lexical tree comprising a model of words; providing scores corresponding to said state identifiers; receiving and storing state identifiers identified by node identifiers identifying a node or group of adjacent nodes in a memory structure; looking up said memory structure to identify particular state identifiers; reading of the scores corresponding to the state identifiers; receiving score updates corresponding to particular state identifiers from a score update generating circuit which generates the score updates using audio input; modifying said scores by adding said score updates to said scores; writing back of the scores to the memory structure after modification of the scores; and selecting at least one node or group of adjacent nodes of the lexical tree according to said scores.
16. A method of speech recognition, comprising providing state identifiers which identify states corresponding to nodes or groups of adjacent nodes in a lexical tree, the lexical tree comprising a model of words; providing scores corresponding to said state identifiers; receiving and storing state identifiers identified by node identifiers identifying a node or group of adjacent nodes in a memory structure; looking up said memory structure to identify particular state identifiers; reading of the scores corresponding to the state identifiers; receiving score updates corresponding to particular state identifiers from a score update generating circuit which generates the score updates using audio input; modifying said scores by adding said score updates to said scores; writing back of the scores to the memory structure after modification of the scores; and selecting at least one node or group of adjacent nodes of the lexical tree according to said scores. 17. The method of claim 16 , wherein for at least some of the states, the node identifier comprises a pointer to a node identifier for another state.