A sharp distinction must be drawn between natural and artificial gesture language. From the primitive natural gestures there are devel oped by imitation, teaching, and convention, nu merous artificial gestures, which are occasional ly of such complexity that their exact origin may be a matter of doubt. As a single instance may be cited the custom of shaking hands to express friendship. This seems to have originally indicated mutual safety, from the fact that the right hands, which alone could hold the sword, were necessarily empty of weapons. Artificial gesture language may be or become altogether conventional or arbitrary in character. Of this type the deaf-mute alphabet is a familiar ex ample. It is obvious, in the light of what has been said, that the gesture language, like oral language, is divisible into dialects. A sign which indicates one thing in a given gesture dialect may indicate a different thing in another dialect, al though dialectic differences are very few in com parison with spoken language. The influence of speech has operated most strongly on gesture language, which is indeed of very limited scope without the aid of speech. Pure gesture lan guage is practically confined to persons or things present before the person using the signs at the instant when he is employing them. Tense and pronoun are unknown, and it seems safe to affirm that gestures correspond not to words, but to sentences in speech. Syntax, therefore, despite
the arguments of certain authorities, seems lack ing in this form of communication. Gesture lan guage, like primitive interjections, which also are shared by man with other animals, is thus pri marily a reflex emotive expression, originally purposeless in character, but gradually developed on account of the necessity of conveying thought, either without or in addition to speech, which is felt by all mankind.
The forms of gesture language which are the most important for the student of language are those employed by deaf mutes, the American Indians, the Neapolitans, and the Cistercian monks, represented in the United States by the Trappist Order, who have taken the vow of per petual silence. See also EXPRESSION ; GESTURE.
Consult: Wundt, Volkerpsychologie, I., Die Sprache (2 parts, Leipzig, 1900) ; Sprachge schichte und Sprachpsychologie (Leipzig, 1901) ; Delbrtick, Grundfragen der Sprachforschung (Strassburg, 1901) ; Jorio, La mimica degli antichi investigata nel gestire Napoletano (Na ples, 1832) ; Mallery, Collection of Gesture-Signs and Signals of the North American Indians, with Some Comparisons (Washington, 1880) ; Sittl, Die Gebarden der Griechen und Romer (Leipzig, 1890).