Playing PFS and thinking of dropping some ranks in Linguistics. What would be some good languages to pick up? Preferably some the more common ones that come up in PFS.
Any of the languages associated with the themes of the seasons would be good ideas: Abyssal, Varisian, Thassilonian, and Tien. Then the languages of the common monsters: Infernal, Goblin, Draconic, Undercommon, Sylvan, Aklo. Perhaps the elemental languages (Terran, Aquan, Auran, Ignan), in case you ever want to summon an elemental. Beyond that, it's a crap shoot; you should just go by character concept.
For a diplomat? Jistka. It's a semi-dead language that's still the lingua franca of the courts of many Inner Sea nations.