2. A method as described in claim 1, further including: calculating one or more such slope parameters for each of a plurality frames from the sequence of frames; and comparing the slope parameters which have been calculated for the sequence of frame against each of a plurality of acoustic models representing speech units, where each such speech-unit model has a model for the slope parameters associated with frame that correspond to the speech unit it represents.
2. A method as described in claim 1, further including: calculating one or more such slope parameters for each of a plurality frames from the sequence of frames; and comparing the slope parameters which have been calculated for the sequence of frame against each of a plurality of acoustic models representing speech units, where each such speech-unit model has a model for the slope parameters associated with frame that correspond to the speech unit it represents. 4. A method as described in claim 2, wherein: said calculating of slope parameters associates one or more slope parameters with each frame of said sequence of frames; said speech-unit model is comprised of a sequence of dynamic programming elements each of which includes one or more slope parameter models; and said comparing includes using dynamic programming to compare the sequence of slope parameters associated with the sequence of frames against the sequence of dynamic programming elements associated with each of said speech unit models.