I don’t know if anyone can actually teach you the language, but there were three users here talking about the subject…
@Lady_Eva was playing with it a few years ago using Enochian as an equivalent and she gave a possible translation for Belial’s enn.
Years later, on the same thread @DerAmateurHexer played with it as well. He did a follow up here.
Last year, @Micah evoked Fastos and Meton. He asked how one could speak and comprehend demonic speech and writing. They gave him specific incantations.
I hope it helps. 