Almost all of the Pathfinder RAW is very rooted in the setting, right down to regions, gods and religions, inter-racial conflicts, and planes. That's why there are such arbitrary language restrictions; to correspond to where these races live and how they interact within the Pathfinder canon.
That being said, any GM outside of a RAW-heavy format (ie. outside of Pathfinder Society Organized Play or a strictly regulated tournament) can bend or break these rules/limitations with ease; all it takes is letting your players know what rules are being bent/broken and why. If you feel language restrictions are impractical, then ignore them when you run your own games or bring it up with a GM you'll be playing with at the character creation stage and see what they say.
I was puzzling over this myself recently while creating a character for a tournament run by a club at my university. Our tournaments are restricted to RAW and only a handful of books, therefore my INT-based Fetchling could only learn Common to start and picked up Alko, Draconic, D'ziriak and Terran as racial options. But this got me thinking about the character's background and I've tried to find more RP-based ways to embrace the limitations and explain them.
Fetchlings can't seem to learn other humanoid languages (Dwarven, Elven, Orcish, etc.), RAW/Pathfinder canon reason being that they generally hail from the Plane of Shadow and wouldn't often deal with these races. My personal justifications for this limitation were: 1) his home city was made up primarily of humans, so everyone spoke Common anyway; and 2) he's a very strictly INT-based, logical, mechanical kind of guy, so learning another well-developed humanoid language with its extensive list of metaphors and idioms doesn't make sense to him, he just doesn't have the head for it. (Thus he could never grasp the flowery Elven language despite his ladyfriend's best efforts to teach him, resulting in a minor background plot point I can work from in RP.)
Tl;dr - A campaign doesn't always have to stick to RAW. Talk to your DM or consider your own house rules. If RAW are being enforced, you can try to satisfy yourself by expanding on the reasons for the restrictions, rather than dwelling on them as being restrictive.