The following tribes speak Caddo:
Arikara -in the Dakotas
Pawnnee
Wichita
Kitsai
The population of Caddo tribes speaking Caddoan
in Texas alone is 5,000.
Other states, LA,OK, SD, ND, AR, etc. also have Caddoan-speaking populations.
Not sure of your source, but I found this on Wiki:
Five languages belong to the Caddoan language family:
Caddo (dialects: Kadohadacho, Hasinai, Natchitoches, Yatasi)
Northern Caddoan Wichita (dialects: Wichita proper, Waco, Tawakoni)
Pawnee–Kitsai Kitsai (also known as Kichai) (†)
Pawnee Arikara (also known as Ree)
Pawnee (dialects: South Bend, Skiri (also known as Skidi or Wolf))
The Kitsai language is now extinct, as its members were absorbed in the 19th century into the Wichita tribe. All of the other Caddoan languages are critically endangered; Caddo is now spoken by only 25 people, Pawnee by 20, Arikara by three, and Wichita by just one tribal elder, Doris McLemore. Caddo, Wichita, and Pawnee are spoken in Oklahoma by small numbers of tribal elders. Arikara is spoken on the Fort Berthold Reservation in North Dakota.
Speakers of some of the languages were formerly more widespread; the Caddo, for example, used to live in northeastern Texas, southwestern Arkansas, and northwestern Louisiana, as well as southeastern Oklahoma. The Pawnee formerly lived along the Platte River in what is now Nebraska.
But let’s say your numbers are correct. 5,000/25,000,000 (Texas population) = 2 x 10^-4 or .02%; a small number indeed. If you want the state to print ballots in Caddo it’s fine with me, but I think you’ll find more people are using the Spanish ones...