I recall reading about a paper where they ran a test on kids just as they had started to learn language, and again a year later after they had learned a lot more.

They did a vocabulary test and played a game. A year later they did another vocabulary test and memory recall challenge. They found that for the kids that remembered the game they played, if they didn't know the word for something at that point, they wouldn't use that word when recalling, even if they had subsequently learned that word in the meantime between tests.

Their conclusion was that memories were closely linked to the vocabulary the kids knew at the time the memory formed.

Been trying to find it again to no avail, sadly.