Synthetic speech sounds were used as input signals to the guinea pig’s auditory nervous system. Single‐unit responses to these signals were recorded from the cochlear nucleus. The results indicate that considerable information concerning acoustic cues of these signals is encoded within the neural responses.Information concerning formant frequency values, formant transitions within the signals, and rate of impulse excitation is present within the firing patterns of individual neurons.Subject Classification: [43]65.48; [43]70.30, [43]65.59, [43]65.42.