1. An interactive method for composing an alphanumeric message by a caller using a telephone keypad, comprising in a messaging terminal the steps of: storing a lexical database from which unigram probabilities, forward conditional probabilities, and backward conditional probabilities for a plurality of words can be recovered; storing a received sequence of key codes that identifies a sequence in which keys on a telephone style keypad are pressed in order to enter the alphanumeric message; generating a word trellis from the sequence of key codes, the word trellis comprising at least one subset of candidate words recovered from the lexical database; determining a most likely phrase having a maximum combined probability determined from the unigram probabilities, forward conditional probabilities, and backward conditional probabilities stored in the lexical database, that consists of a combination of one candidate word from each of the at least one subset of candidate words; generating a most likely message from the most likely phrase and presenting the most likely message to the caller; and confirming that the most likely message is the alphanumeric message.
1. An interactive method for composing an alphanumeric message by a caller using a telephone keypad, comprising in a messaging terminal the steps of: storing a lexical database from which unigram probabilities, forward conditional probabilities, and backward conditional probabilities for a plurality of words can be recovered; storing a received sequence of key codes that identifies a sequence in which keys on a telephone style keypad are pressed in order to enter the alphanumeric message; generating a word trellis from the sequence of key codes, the word trellis comprising at least one subset of candidate words recovered from the lexical database; determining a most likely phrase having a maximum combined probability determined from the unigram probabilities, forward conditional probabilities, and backward conditional probabilities stored in the lexical database, that consists of a combination of one candidate word from each of the at least one subset of candidate words; generating a most likely message from the most likely phrase and presenting the most likely message to the caller; and confirming that the most likely message is the alphanumeric message. 3. The method according to claim 1, wherein the step of generating a word trellis from the sequence of key codes comprises the steps of: determining N subsequences of the received sequence of key codes, wherein the N subsequences are subsequences of key codes separated within the received sequence of key codes by a predetermined key code; and recovering the at least one subset of candidate words from the lexical database based on an input to the lexical database of one of the N subsequences.