Children learn by mimicking and remembering. It takes Avery much longer to commit a concept to memory, so she must repeat. Repeat. Repeat. Repeat. Repeat.
She'll watch the same television show over and over. This includes Max and Ruby. *stabs parental eardrums with pointy stick*
She also repeats phrases and songs, the ABCs, names of the people she knows and places she's been and many, many other things.
We understand the importance of her rehearsing these concepts. Strangers do not.
It's somewhat amusing to watch the reactions Avery gets when she says, "Bye man!" a dozen or so times to the same guy at the grocery store. Most people will actually return or at least acknowledge each one. Bless their patient hearts. I'll often redirect her to spare these busy people the last six or seven farewells.
Most of the time these repetitions are necessary. Though sometimes she repeats herself out of habit or because she's distracted or not focusing. And then there are times when she does it just to push her mother's buttons.