C.L.E.E.S.E. (Combinatorial Expressive Speech Engine) is a tool designed to generate an infinite number of natural-sounding, expressive variations around an original speech recording. More precisely, C.L.E.E.S.E. creates random fluctuations around the file’s original contour of pitch, loudness, timbre and speed (i.e. roughly defined, its prosody). One of its applications is the generation of very many random voice stimuli for reverse correlation experiments, or whatever else you fancy, really.