20. A method for identifying an unknown utterance as one of a set of reference words comprising the steps of generating a first signal representative of the prediction parameters of each of a plurality of utterances of a reference word; generating at least one template signal for each reference word responsive to the reference word first signals, each template signal being representative of a group of the reference word first signals; generating a second signal representative of the prediction parameters of said unknown utterance; jointly responsive to the template signals of each reference word and the second signal, forming a set of signals each representative of the distance between said second signal and said reference word template signal; responsive to the distance signals of all reference words, identifying the unknown utterance as the reference word having the minimum distance signals characterized in that said template signal generation for each reference word includes generating and storing a set of signals each representative of the distance between a pair of reference word first signals responsive to the first signals of said reference word; and successively partitioning the first signals of said reference word into clusters responsive to the stored reference word distance signals, the first signals of each cluster having a predetermined degree of similarity; determining the centermost first signal of each cluster responsive to said stored reference word distance signals; and identifying said centermost first signal as the cluster template signal.
21. A method for identifying an unknown utterance as one of a set of reference words according to claim 20 characterized in that the successive partitioning further includes determining the centermost of said first signals of said reference word and identifying the first group of said reference word first signals which are within a predetermined distance of said determined centermost first signal responsive to said reference word stored distance signals; successively forming groups of first signals having a predetermined degree of similarity comprising determining the centermost first signal of the immediately preceding group from the stored distance signals and identifying the first signals of the immediately preceding group which are within a predetermined distance of the centermost first signal of the immediately preceding group as members of the next group of first signals; and responsive to all first signals of the immediately preceding group being within the predetermined distance of saidimmediately preceding group centermost first signal, identifying the immediately preceding group as a cluster of first signals having said predetermined degree of similarity.