Quote Originally Posted by Hecuba View Post
If you can find a way to understand Druidic (fairly easy with magic), they you simply need a reason not to speak it.

A good option here is for the NPC to simply pass as mute. Then you're only tripped up by writing.

I would suggest finding a some way to communicate without speaking.
My preference would be to have custom magic item made and learn Drow Sign language.

Continuous ring of Nystul's Magical Aura & Comprehend Languages is safely under 10k gold (what with the 1st level spells and all).

EDIT, given the limited item availability post:
If you can pass the Comprehend Languages without the Magical Aura, Comprehend Languages is actually on your list.
here is the problem. druids have a spell for muteness.

on the other hand, last i knew druidic was not allowed as a written language