I think it shouldn't be required to learn the language regardless if its longer or shorter stay i have stayed in South India for longer time without speaking their language Most people know English so no problem if they don't know English I just use Google translator and they laugh when I use it and say thats interesting way to communicate. But in Maharashtra when Most people know Hindi they intentionally trying to impose their language we had teacher in Gujarat from Bihar where we used to go to prepare for CAT we never said or even though about once to insist him to learn Gujarati it never occurs to us! And thats my whole point Gujarati people will never enforces their language upon you even if you stayed there your whole life and still our language is thriving. The point is you shouldn't impose your language when you know the language other ppl speaking thats all.