Update: As a few other posters have mentioned, this quest is a breadcrumb quest and becomes irrelevant if you've already completed some quests, namely Primalist Pillagers and/or Honor Their Sacrifice. If you did these before 10.0.7 went live, you won't have received the letter in the post and it also prevents you from accepting it from the adventure journal. However, the macro to check for quest completion still returns 'false' and it still shows up in the journal, hence the confusion.
If you're looking for where to go in this situation, visit Sonova Snowden in Azure Span and pick up Academic Acquisitions. You can then grind mobs in The Azure Span to get Liberated Furbolg Artifacts and after the initial hand-in, it will turn into a repeatable quest which will increase your language skill each time.
Thought it'd update this post since the Winterpelt language skill recently became a requirement for the new meta-achievement. Had forgotten all about this until I went to complete it for the achievement myself. Hope it helps!
Original Comment:
Anyone else had trouble finding this quest? I've completed the pre-requisites (as far as I know) but I didn't get any mail and can't accept it from the adventure journal.