Green’s Dictionary of Slang

(US) to shout, to yell.

1892		S. Crane in N.-Y. Trib. 10 July in Stallman (1966) 4: [He] began to yell, and ki-yi, and whoop.
1940		F. Hunt Long Trail from Texas 14: He wanted to ki-yi, but he knew that might frighten the herd.