3. The apparatus of claim 2 wherein said deleted estimation processor includes: means for dividing label inputs generated by the acoustic processor means during utterance of sample text into two portions; means for applying a forward-backward algorithm to the basic label output probabilities for one of the two portions of labels to produce counts C*.sub.1 and probabilities P*.sub.1 ; means for applying a forward-backward algorithm to the basic label output probabilities for the other portion of labels to produce counts C*.sub.2 and probabilities P*.sub.2 ; smoothing processor means, which receives as input the counts C*.sub.1 and C*.sub.2 and the probabilities P*.sub.1 and P*.sub.2 together with smoothed label output probabilities, for producing final label output probabilities ##EQU16## wherein .lambda.*.sub.m is selected to maximize the likelihood of the final label output probabilities corresponding to spoken text and wherein A.sub.ij represents a transition from a state i to a state j in a phone machine.
3. The apparatus of claim 2 wherein said deleted estimation processor includes: means for dividing label inputs generated by the acoustic processor means during utterance of sample text into two portions; means for applying a forward-backward algorithm to the basic label output probabilities for one of the two portions of labels to produce counts C*.sub.1 and probabilities P*.sub.1 ; means for applying a forward-backward algorithm to the basic label output probabilities for the other portion of labels to produce counts C*.sub.2 and probabilities P*.sub.2 ; smoothing processor means, which receives as input the counts C*.sub.1 and C*.sub.2 and the probabilities P*.sub.1 and P*.sub.2 together with smoothed label output probabilities, for producing final label output probabilities ##EQU16## wherein .lambda.*.sub.m is selected to maximize the likelihood of the final label output probabilities corresponding to spoken text and wherein A.sub.ij represents a transition from a state i to a state j in a phone machine. 4. Apparatus as in claim 3 wherein the smoothing processor means includes means for evaluating .lambda.*.sub.m according to the expression: ##EQU17## where S*.sub.m represents an mth class of transitions such that EQU S*.sub.m ={A.sub.ij .vertline.T.sub.m-1 &lt;C*.sub.1 (A.sub.ij)+C*.sub.2 (A.sub.ij)&lt;T.sub.m }; wherein T.sub.m represents a predefined count range limit and wherein each class of transitions is defined between a pair of adjacent range limits.