A system and method for speech recognition using an enhanced phone set comprises speech data, an enhanced phone set, and a transcription generated by a transcription process. The transcription process selects appropriate phones from the enhanced phone set to represent acoustic-phonetic content of the speech data. The enhanced phone set includes base-phones and composite-phones. A phone dataset includes the speech data and the transcription. The present invention also comprises a transformer that applies transformation rules to the phone dataset to produce a transformed phone dataset. The transformed phone dataset may be utilized in training a speech recognizer, such as a Hidden Markov Model. Various types of transformation rules may be applied to the phone dataset of the present invention to find an optimum transformed phone dataset for training a particular speech recognizer.