imported post
Chronology...
YeeeeeeeeHaaaaaaaaaaaa! Rebel Yell
YeeHaw! Redneck Yell
Iiiiiiieeeee! Cajun Yell
HooHaa! Mad Magazine Yell (circa late 1950's) The word "hoohah" was a running gag in the early years of Mad, often exclaimed by characters in the comic book issues written and edited by Harvey Kurtzman. Its somewhat Eastern European feel was a perfect fit for the New York Jewish style of the magazine. Kurtzman liked using Yiddish expressions and nonsense words to humorous effect, and the very first story in the first issue of Mad was even titled "Hoohah!" The word's precise origin is unknown, although it may have sprung from the Hungarian word for "wow".
hoohahhas also become a slang term for female genitalia
Hooah! Phonetic spelling of the military acronym HUA, which stands for "Heard Understood Acknowledged." Originally used by the British in the late 1800's in Afghanistan. More reciently adopted by the United States Army to indicate an affirmative or a pleased response.
I believe the other services have since copied the Army's 'Hooah' response (I heard it once) but dunnohow it went.