Patent ID: 7006971

Claim:
A method of recognizing a speech utterance (s) available in spelled form, comprising: a first processing stage in which a corresponding letter sequence (r) is estimated by means of a letter speech recognition unit ( 2 ) based on hidden Markov Models, said letter speech recognition unit not using a letter grammar which denotes probabilities of the occurrence of different possible letter combinations; and a second processing stage ( 3 ) in which the estimated result (r) produced by the first processing stage utilizing a statistical letter sequence model ( 4 ) and a statistical model ( 5 ) for the speech recognition unit ( 2 ) is post-processed, wherein a dynamic programming method is used during the post-processing wherein a grid structure on which the dynamic programming is based and whose node points are provided for the assignment to accumulated probability values, is converted into a tree structure and an A* algorithm is used for finding an optimum tree path.