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1.
1) what a person might say, mid-sentence, to shorten a story to get to the point of a discussion 2) what a person might say to hide any incriminating activities that they may have been involved in
(ex. Yada, Yada, Sex with someone else or Yada, Yada, Shoplifting)
by Jason June 30, 2004
 
2.
It exactly sounds to me the words Japanese small children use resisting to some suggestion their parents give, acting like a baby.

Originally, it is Iyada(dislike) but colloquially it souds like yada.
A child has a special choice to get at a shop but his or her mother recommends something else for some reasons with which they try to persuade hard. The child says,” yada, yada, yada, I prefer to my choice”.
by zkamakura May 03, 2010