Much past research has been devoted to deciding, for any given speech segment, whether it is “voiced” or “voiceless.” In reality, however, speech often combines both glottal and supraglottal excitation, so that such a binary classification can be essentially invalid. We have begun a study of speech produced with mixed excitation with the two major goals of (1) determining the best analytic tools for this type of analysis and (2) examining a variety of real and modeled speech signals for their excitation characteristics. Initial research strategies and preliminary results will be discussed. [Research supported by NSA.]