I'd first ask myself where do I want to be: enterprise, freelance, community/FLOSS, ...? After that, it's not hard to make list of langs that are mostly used in

I'd first ask myself where do I want to be: enterprise, freelance, community/FLOSS, ...? After that, it's not hard to make list of langs that are mostly used in these areas and personally i'd choose langs that are in more than one area. Ok, this has one big flaw, it doesn't tell much about langs that are still in development (rust, go, ...), so keep that in mind.