This study addresses how characteristics of different talkers and the varying information in the auditory signal produced impacts the audio-visual performance of listeners.  Degraded speech syllables were acoustically analyzed to evaluate individual acoustic characteristics.  Based on generated behavioral confusion matrices we hope to explain why listeners confuse certain stimuli for others.  We are specifically focusing on F2 transitions of the waveforms and voice onset time differences. The results of the present study provide the foundation for understanding what acoustic patterns and talker qualities are desirable for optimal audio-visual speech integration and might also have implications for the design of future aural rehabilitation programs.