Assassin's Creed fansite Access the Animus has worked with Montreal's Kanien'kehá:ka Onkwawén:na Raotitióhkwa Language and Cultural Center to translate all of the unsubtitled dialogue in Valhalla's Vinland arc.
The video below reveals what is being said in all of the conversations going on around Eivor in this part of the game, which she (and you) are deliberately left unable to understand.
As well as dialogue, it includes translations of item descriptions and more. There's also a fascinating explanation of the Mohawk creation myth Eivor hears around the campfire - previously told by the Oneida tribe in Assassin's Creed Rogue. Intriguingly, there are differences in the stories which accurately depict the differences in its telling by the two tribes.
I enjoyed the Vinland section of the game, which was a real change of pace from the rest of Valhalla. You can dip in and out at any time if you do want to get on with other things, and using Valhalla's recently-added transmog system you can now wear its unique clothing set elsewhere in the game.
Assassin's Creed has long featured Native American culture and language in its games, dating back to Assassin's Creed 3. Like Valhalla (and AC3 spin-off Rogue), Ubisoft has worked to portray the culture as accurately as possible.
Access the Animus previously worked to translate Valhalla's fictional Isu language, which was put together as a secret code for fans to unravel by some seriously-talented Ubisoft developers. Runes in the game and on its special edition packaging led to a secret in-game item - which took fans months to find.