Martin. Robinson played almost exclusively in Black nightclubs until 1928. He wasn’t in Hollywood before that. Exactly when Robinson started using the word I haven’t found. He certainly may have popularized it at sometime.
Since the word is used in two stories in [i[Variety* in 1921 and 1922, one assumes the story that Robinson invented the word probably isn’t true. I know that you didn’t say that. You were merely speculating about where Robinson might have gotten the word. And, of course, he could have worked with a Yiddish speaking performer prior to 1919, and heard the word from that source.