This little baby girl has evidently developed a new syllable that sounds remarkably identical to the f-bomb. She starts saying it in the back seat of the car with her older brother, who at the very least understands that it's a word they aren't supposed to say.
A silly argument (if you can even call it that) inevitably ensued.
WARNING? There is child profanity in this video.
Probably the silliest thing about this is how the little baby clearly doesn't know what she's saying, probably has no idea that there's even any meaning behind it at all, and just keeps doing it to get her brother's reaction. For all she knows, she could just as easily be saying "wep" or "dut" or some other spunky little syllable.