11. A method for recognizing a speech pattern as a string of predetermined reference words comprising the steps of: storing a set of signals representative of the time frame sequence of acoustic features of each reference word, said sequence having a beginning frame and an ending frame; producing a set of signals representative of the time frame sequence of acoustic features of the speech pattern; generating at least one reference word string responsive to the speech pattern acoustic feature signals and the reference word acoustic feature signals; and identifying the speech pattern as one of the generated reference word strings characterized in that said reference word string generation comprises: producing a set of signals identifying successive reference word levels; assigning a segment of the speech pattern to each successive level; for each level, time registering the level speech pattern segment feature signals with the feature signals of the reference words to produce level time registration speech pattern segment endframe signals and time registration correspondence signals for said reference words, and selecting reference word strings responsive to the time registration speech pattern endframe and time registration correspondence signals of the levels.
11. A method for recognizing a speech pattern as a string of predetermined reference words comprising the steps of: storing a set of signals representative of the time frame sequence of acoustic features of each reference word, said sequence having a beginning frame and an ending frame; producing a set of signals representative of the time frame sequence of acoustic features of the speech pattern; generating at least one reference word string responsive to the speech pattern acoustic feature signals and the reference word acoustic feature signals; and identifying the speech pattern as one of the generated reference word strings characterized in that said reference word string generation comprises: producing a set of signals identifying successive reference word levels; assigning a segment of the speech pattern to each successive level; for each level, time registering the level speech pattern segment feature signals with the feature signals of the reference words to produce level time registration speech pattern segment endframe signals and time registration correspondence signals for said reference words, and selecting reference word strings responsive to the time registration speech pattern endframe and time registration correspondence signals of the levels. 12. A method for recognizing a speech pattern as a string of predetermined reference words according to claim 11 further characterized in that said time registering comprises: restricting the range of time registration starting frames for the current level responsive to the time registration speech segment endframes of the immediately preceding level; and storing for each time registration speech segment endframe the best correspondence signal for said endframe, a signal representative of the best correspondence signal reference word for said endframe, and a signal representative of the time registration speech pattern starting frame corresponding to the best reference word for said endframe.