My Dad served in Vietnam from January 1970 to January 1971 as a Marine with the First Marine Division Alpha and Charlie Company 2nd Platoon.
A few months after arriving in Nam, he volunteered to become a Radioman...no one really wanted that job because it was very dangerous, the enemy made certain that he would be the first to get killed. No radio no support.
My Dad step up to becoming a Radioman...he told me that his vocabulary was limited and he had trouble pronouncing many english words. He mostly spoke Tex/Mex. But he was a very big and strong man.
He told me that the rules were very simple, to say "No" was to say Negative, to say "Yes" was to say Affirmative, and a sacred word was the word "Repeat" (had something to do with artillery and friendly fire)...well he could not pronounce word "Affirmative"...not that the Marines in his Unit were making fun of him, it's because his way of saying affirmative sounded very funny.
So one day somewhere in the Jungle's of Vietnam, he got tired of been laughed at trying to say "Affirmatiive". Around April of 1970, instead of saying affirmative, he was the first to come up with the Radio expression, "Roger That" instead of Affirmative.
Today "Roger That" is commonly used in War Movies and by many who served in the Military...Thank you Dad...we love you and also for telling us your War Stories.
Ben
Seabrook, TX