Frnk (or Frnck, because English language publisher uses two spellings for some reason) might qualify. Main character is an orphan who grew up in modern times, but got transported to prehistoric-like world. There he is taken in by a tribe of prehistoric humans, who don't use vowels.
That prehistoric world might or might not be the place that he originated from.
It's a pretty good book, especially as far as all-age adventure stories go.