Since I've been musing about fiction recently, here's another thought that crossed my mind.

Fantasy fiction often has a magic system involving spells cast in spoken language. But what language? Why does that language work and not another? Or would another language work? Would it depend on the spell? On the caster? On the location? It seems to me that there are quite a few plausible ‘cosmologies of magic’ which would cause different answers to those questions, many of which have specific examples in existing fiction, and I wonder if there are any more I've missed out.

So, what have I missed?