Where would you recommend staying?
That answer is totally up to you and your comfortability! I've listed several hotel recommendations that are beautiful but I've also found that the best way to travel to Sevilla is by staying in a local air b&b!
So explore around and decide what sounds more fun for you to do!
Is it hard to get around?
No! If you are able to walk, most everything is incredibly accessable on foot. If not, UBER makes for quick and easy alternative.
Is the language barrier a problem?
Absolutely not. In fact, most everyone can speak English or will try their best. Although, I always encourage anyone traveling to a different country to at least greet their servers etc. in THEIR language before speaking English to them.
Traveling to & from airport?
Taxi & UBER! Europe also has their own form of UBER called BOLT