Phonetic units are identified in a body of utterance data according to a novel segmentation approach. A body of received utterance data is processed and a set of candidate phonetic unit boundaries is determined that defines a set of candidate phonetic units. The set of candidate phonetic unit boundaries is determined based upon changes in Cepstral coefficient values, changes in utterance energy, changes in phonetic classification, broad category analysis (retroflex, back vowels, front vowels) and sonorant onset detection. The set of candidate phonetic unit boundaries is filtered by priority and proximity to other candidate phonetic units and by silence regions. The set of candidate phonetic units is filtered using no-cross region analysis to generate a set of filtered candidate phonetic units. No-cross region analysis generally involves discarding candidate phonetic units that completely span an energy up, energy down, dip or broad category type no-cross region. Finally, a set of phonetic units is selected from the set of filtered candidate phonetic units based upon the probabilities of candidate boundaries defining the ends of the unit and within the unit.