Dogs react primarily to sounds and coustic signals, and not to language. Therefore the whistle is optimal for training and hunting as the sound can hardly be heard. Its sound is clearly different from the ususal sounds that surround your dog every day. Please note that a light whistle is completely sufficient, as sounds that are too loud rather frighten your dog. Dogs have a significantly wider sound spectrum and perceive the tones of the high frequency whistle in the same volume as a normal dog