Nonlinguistic communication may be conventional or spontaneous. Conventional nonlinguistic means of communication consist of gestures incomprehensible to the uninitiated, usually stipulated beforehand and sometimes codified into rules of usage. They may be international, national, or narrowly restricted; for example, the signals used by soldiers or the sign language of monastic orders. Spontaneous gestures are divided into four groups: pointing gestures, gestures that convey or reveal emotions, emphatic gestures, and rhythmical gestures.