A dog bark limiter includes a housing (2) supported against the dog's skin by a strap, stimulus electrodes (5), and a sensor (6) for producing signals in response to vocalizing by the dog. The sensor includes a membrane (6) supported by the surface (9) for efficiently transmitting sound energy through the housing and a rigid nipple (11) engaging the membrane. Control circuitry in the housing has an input coupled to an output of the transducer and output terminals coupled to produce aversive stimulus signals between the first and second electrodes in response to the signals produced in response valid barking by the dog. A motion detector (40) produces a motion detection signal in response to a characteristic movement of the portion of dog that accompanies barking by the dog and aids in detecting a valid bark. A controller (33) executes a frequency capture routine to produce a frequency spectrum of the dog's vocalizations and compares it with a valid bark spectrum to determine if the vocalization constitutes a valid bark.