That’s stretching it. Perhaps the ta-ta came from a baby’s da-da-da babble.
Now, about blah blah at the beginning of this old thread, in one of Bruce’s last bits he talked about his obscenity trial where a judge or lawyer or cop used blah blah for all the supposedly dirty words Bruce used.
samclem’s pointer to the Louis Armstrong cover seems a reasonable origin of yada yada to me. It’s something Bruce would have definitely known.
Another usage from about the same time: in May 1945, Bing Crosby and Judy Garland had a Top 10 hit with a novelty song called “Ya-Ta-Ta Ya-Ta-Ta (Talk, Talk, Talk).” In the song, Judy discusses her latest shopping spree only to have Bing interrupt and complain “all of your ya-ta-ta, ya-ta-ta, talk, talk, talk.” Later, Bing talks about his golf game and gets the same response from Judy.