If you could learn three languages to set you up for all other languages what would they be
If you wanted to become a polyglot and you needed to pick three very different languages to give you as diverse a grounding as possible what would they be I thought maybe a tonal language and a language with an interesting Case system or something but I'm still thinking PS also what is the aspect of a language you've learned that's most done your head in
Not because Esperanto is spoken around the world or related to a bunch of other languages, but because learning Esperanto teaches you how to learn other languages. I once saw learning Esperanto compared to learning the recorder (musical instrument). It is not that you are going to be a great recorder player, it is that learning the recorder teaches you skills easily that form a good basis when learning more sophisticated instruments.
Russian as the Indo-European representative, since it has a fairly complex grammar and it's still widely-spoken. Mandarin, for the characters and all the influence Chinese had in other Asian languages. Arabic to complete the mix and cover the Middle East and Northern Africa.