Abstract: Knowledge based speech recognition apparatus and methods are provided for translating an input speech signal to text. The speech recognition apparatus captures an input speech signal, segments it based on the detection of pitch period, and generates a series of hypothesized acoustic feature vectors for the input speech signal that characterizes the signal in terms of primary acoustic events, detectable vowel sounds and other acoustic features. The apparatus and methods employ a largely speaker-independent dictionary based upon the application of phonological and phonetic/acoustic rules to generate acoustic event transcriptions against which the series of hypothesized acoustic feature vectors are compared to select word choices. Local and global syntactic analysis of the word choices is provided to enhance the recognition capability of the methods and apparatus.