2. A continuous speech recognition system for recognizing an input speech composed of a plurality of continuously spoken words comprising: a speech analyzing means for analyzing an input signal at every given frame time point m and outputting an input pattern expressed in a time series of a feature vector comprising a predetermined number of feature parameters; an input pattern memory to store said input pattern; a reference pattern memory to store a reference pattern comprising a feature vector in the same format as said input pattern for each of a plurality (V) of predetermined words to be recognized; a distance calculating means to calculate the distance between the feature vector of said input pattern at a time point m and the feature vector of the reference pattern of the v-th word at a time point n at every time point n under a predetermined distance formula by changing the time point n of the reference pattern of the v-th word in an arbitrary order from the start point to end point N.sup.v while changing the reference pattern V from the first word to end word V for each time point to end point M; an asymptotic calculating means to calculate a similarity measure D(l, v, n) given by the cumulative sum of said distances on the l-th digit at said time points n and a path information F(l, v, n) indicating a time point of the input pattern at the start point of said v-th reference pattern on a path through which said similarity measure D(l, v, n) has been obtained by a predetermined asymptotic expression according to a dynamic programming process while changing the time point n of the reference pattern of the v-th word in an arbitrary order from the start point to end point N.sup.v, while changing digit number l from one to L, and while changing the reference pattern v from the first word to the end word V for each time point m of the input pattern, said time point m changing from the start point to end point M; a digit similarity measure and digit path information calculating means to select a minimum similarity measure from among the similarity measures at the end time points of the reference patterns of all the words on the l-th digit obtained through said asymptotic calculating means, and to provide said minimum similarity measure as a digit similarity measure DB(l, m), a category to which the word corresponding to said minimum similarity measure belongs as a digit recognition category W(l, m)=v, and path information corresponding to said minimum similarity measure as a digit path information FB(l, m) on said digit l at said time point m while changing digit number l from one to L for each time point m of the input pattern, said each time point m changing from the start point to end point M; an initializing means to give said digit similarity measure DB (l-1, m-1) as an initial value of said similarity measure at a time point (m-1) and to give time point (m-1) as an initial value of said path information at a time point m while changing the line point m of the input pattern from the start point to end point M; a decision means to obtain a final digit from said similarity measure DB(l, m), to obtain a recognized result at said final digit from said digit recognition category W(l, M), at the end point M of said input pattern, to obtain an end point of said input pattern on the digit previous to the final digit by one from said digit path information at the end point M, to obtain a recognized result of the digit prior to said final digit by one from said digit recognition category at the end point, and to obtain a recognized result at each digit sequentially toward the start point of said input pattern.
2. A continuous speech recognition system for recognizing an input speech composed of a plurality of continuously spoken words comprising: a speech analyzing means for analyzing an input signal at every given frame time point m and outputting an input pattern expressed in a time series of a feature vector comprising a predetermined number of feature parameters; an input pattern memory to store said input pattern; a reference pattern memory to store a reference pattern comprising a feature vector in the same format as said input pattern for each of a plurality (V) of predetermined words to be recognized; a distance calculating means to calculate the distance between the feature vector of said input pattern at a time point m and the feature vector of the reference pattern of the v-th word at a time point n at every time point n under a predetermined distance formula by changing the time point n of the reference pattern of the v-th word in an arbitrary order from the start point to end point N.sup.v while changing the reference pattern V from the first word to end word V for each time point to end point M; an asymptotic calculating means to calculate a similarity measure D(l, v, n) given by the cumulative sum of said distances on the l-th digit at said time points n and a path information F(l, v, n) indicating a time point of the input pattern at the start point of said v-th reference pattern on a path through which said similarity measure D(l, v, n) has been obtained by a predetermined asymptotic expression according to a dynamic programming process while changing the time point n of the reference pattern of the v-th word in an arbitrary order from the start point to end point N.sup.v, while changing digit number l from one to L, and while changing the reference pattern v from the first word to the end word V for each time point m of the input pattern, said time point m changing from the start point to end point M; a digit similarity measure and digit path information calculating means to select a minimum similarity measure from among the similarity measures at the end time points of the reference patterns of all the words on the l-th digit obtained through said asymptotic calculating means, and to provide said minimum similarity measure as a digit similarity measure DB(l, m), a category to which the word corresponding to said minimum similarity measure belongs as a digit recognition category W(l, m)=v, and path information corresponding to said minimum similarity measure as a digit path information FB(l, m) on said digit l at said time point m while changing digit number l from one to L for each time point m of the input pattern, said each time point m changing from the start point to end point M; an initializing means to give said digit similarity measure DB (l-1, m-1) as an initial value of said similarity measure at a time point (m-1) and to give time point (m-1) as an initial value of said path information at a time point m while changing the line point m of the input pattern from the start point to end point M; a decision means to obtain a final digit from said similarity measure DB(l, m), to obtain a recognized result at said final digit from said digit recognition category W(l, M), at the end point M of said input pattern, to obtain an end point of said input pattern on the digit previous to the final digit by one from said digit path information at the end point M, to obtain a recognized result of the digit prior to said final digit by one from said digit recognition category at the end point, and to obtain a recognized result at each digit sequentially toward the start point of said input pattern. 20. A continuous speech recognition system according to claim 2, wherein said distance calculating means comprises an absolute value circuit to output the absolute value of the difference between the feature parameter comprising said input pattern and the feature parameter comprising said reference pattern, an adder circuit with an input being an output of the absolute value circuit, and a register to store the output of said adder circuit and also to output the stored contents to the other input of said adder circuit.