The invention for processing speech that is described herein measures the simultaneous periodic changes of multiple acoustic features in a digitized utterance without regard for lexical, sublexical, or prosodic elements. These measurements of periodic, simultaneous changes of multiple acoustic features represent transformational structures contained in speech. Various types of transformational structures are identified, quantified, and displayed by the invention. The invention is useful for the study of such speaker characteristics as cognitive, emotional, linguistic, and behavioral functioning, and may be employed in the study of other phenomena of interest to the user.