Inspired by the recent post about Arrival / The Story of Your Life

The idea of linguistic relativity ... is a principle suggesting that the structure of a language influences its speakers' worldview or cognition, and thus individuals' languages determine or influence their perceptions of the world.

There's, of course, a lot more to it, many variations, and all still at least somewhat in dispute.

Nevertheless, as the title says, assume it's true, and speculate on which languages would be the most interesting to learn from an "expand your mind" perspective.