Speech recognition relies on a complex interaction between the sensory information supplied by the ear and the pattern recognition by the brain. Recent advances in defining the role of sensory information in speech understanding have come from work with the cochlear implant, a sensory prosthesis that restores hearing to the profoundly deaf. Artificial electrical stimulation of the auditory nerve provides an opportunity for evaluating the interaction between the quality of sensory information and auditory pattern recognition. The results have been somewhat surprising.