I'm writing an adventure high fantasy, and I have found it very helpful to have a map to look at. Admittedly, I rarely look at it, but I feel that since I drew it out, I have had a much better understanding of where everything is. Maps, for me, prevent me from contradicting myself in regards to direction. i.e. X city is southwest of Y city, not southeast.
Of course, you do not need a map. The small your world is, the less important and helpful it becomes. IDK what the scal of your plot is, so...
I have dabbled in the idea of a language. It's fun, but definitely not necessary. A language can add a lot, but if done incorrectly, it can definitely make your story worse. I failed at making my language consistent, and had to go back and rework a lot of the words (fortunately I didn't use much).
That being said, neither is necessary. I suggest spending fifteen minute sketching out a map, because it is fun. I suggest, not working with a new language unless it is central to your story or adds a lot to the world.