Jatta Jatta has no meaning to its words its a slang. Dutch people use it to express emotion and is mostly referenced with a happy or uplifting emotion. It could be used to greet people or when you have no clue how to react to certain situations.
Person1: Hey dude!
Person2: Jatta Jatta!
Person2: Jatta Jatta!
by Lyriss July 21, 2019