The sign language of the North American Plains Indians was in use from Manitoba in Canada in the northern Plains to New Mexico in the south, and it was used to overcome language barriers between individuals or groups of the various tribes. The examples in this article stem from Sign Talk of the Cheyenne Indians and Other Cultures by Ernest Thompson Seton, who collected the symbols at the end of the 19th century, and published the book 1918 in New York. There were several publications on Indian Sign language before Seton, and there are several recent works on the topic, which I won't mention in particular, they can be found searching the Internet.
Most gestures/signs illustrated by Seton appear very intuitive, which suggests that they could be understood even by persons unfamiliar with that particular sign. But as Seton suggests, this sign language was commonly known and much used. Some few signs seem to have a certain universal character, as I have seen them used today by persons who definitely have no idea of Indian sign language; an example is the sign/gesture for 'idea', another one is the sign for 'forget/forgot', both included in this article. Of course there might have been influences to and from other sign languages, and it can't even be excluded that certain gestures may have spread, or be incorporated.
The Plains Indians Sign Talk includes numerals and even a 'manual alphabet' employing hand signs to signal the letters of the Latin alphabet. As Seton explains, while this might not have been useful for most Indians, it allowed to spell proper names of places and persons.
Captain William Philo Clark gives an illustration of the semantics of PlainsSign Talk (Clark 1885, via Seton 1918; Clark's work according to Seton comprising over 1000 signs).
"I arrived here to-day to make a treaty — my one hundred lodges are camped beyond the Black Hills, near the Yellowstone River. You are a great chief — pity me, I am poor, my five children are sick and have nothing to eat. The snow is deep and the weather intensely cold. Perhaps God sees me. I am going. In one month I shall reach my camp."
Sign Talk (literally)
"I—arrive here—to-day—make—treaty. My—hundred—lodge—camp—beyond—Hills—Black—near—river—called—Elk—you—chief—great—pity me—I—poor—My—five—child—sick—food—all gone/wiped out—Snow—deep—cold—brave/strong. Perhaps—Chief Great/Mystery Great—above—see—me—I—go. Moon—die—I—arrive there—my—camp."
The English translation "in one month" appears to be inaccurate, as the signs transliteration "moon die" rather means new moon. As we don't know the moon phase at the time of the utterance, we can only assume a period of minimum a few days, probably more.
Seton's book is organized alphabetically like a dictionary. Following, I give one example per letter of the alphabet. The drawings are by Seton, and I'm citing the according explanations from Seton.
Abandon, Give It up (Thrown away, chucked). Hold both S hands,, backs up, near left breast, briskly swing both down to left side, opening them with a snap and giving a slight rebound to the hands after the movement, as though emphatically throwing away something. Sometimes only one hand is used. Compare Bad, Hate, and Charge. See Divorce.
Fr. abandonner; Ger. aufgeben.
Band or Patrol (Banded together). Hold the compressed left hand compressed pointing up; encircle it with the right forefinger and thumb. (Chasing Bear.) Not a true Indian sign and not used, but would understand it. (Seger.) Sometimes use bunch or few. See Tribe or Troop.
Fr. la bande, la patrouille; Ger. die Schar, die Truppe.
Centre. With thumbs and index fingers of L hands make a horizontal circle; then, keeping the left unchanged, indicate centre with right G finger. Sometimes draw a horizontal circle with right G, then drop same down into its centre.
Fr. le centre; Ger. die Mitte.
Defiance, Defy, Dare, Challenge, or I defy you. Point the T hand toward the person. This is an extremely insulting challenge implying also the extreme of hatred and contempt. See Challenge.
Fr. le défi, défier; Ger. die Herausforderung, trotzen.
Forget or Forgot (Swept from my brain). Touch the forehead with the right N finger. Shake the head and motion as though to brush away an imaginary fly from near the nose. (Sheeaka and Pop). See Remember not. (...)
Fr. oublier; Ger. vergessen.
Ghost, Soul, or Spirit. Bring right G hand in front of centre of body, pointing down; then draw it upward, as though drawing the forefinger out of the mouth, upward and to the front and at the same time exhale a breath. (Scott) The Cheyennes sign Big eyes (as in Owl), and shaking the hands at the same time. See Spirit.
Fr. l'esprit; Ger. der Geist.
Idea, Thought (Thought expressed). Lay the right G on the forehead, pointing up, palm to left; swing it down to horizontal at mouth level, then push it straight forward and up in a curve. Compare So.
Fr. l'idée, la pensée; Ger. die Idee, der Gedanke.
[Will be continued in part 2]