Heck. even I don't remember everything I said in every story!
But, I would say that Esperanto, being a constructed language without a home or culture, and not the first language of anyone, could be honestly overlooked in the teaching of human world languages. I don't think elves learn Communicationssprache, Ido, Interlingue, Mondial, Interglossa, or any of the other two-dozen or so constructed languages out there, either. What would be the point? Anyone speaking a constructed language would have to have a first language, which the elf would know.
That's my story, and I'm stickin' to it!