From the transcript

It will be the first opera entirely sung in Tlingit. There will, however, be some things for most of the audience who who won't understand fluent Tlingit, there will be a program which will show the summary of the entire thing, so you can follow scene by scene if you want, or read up on it real quick before the lights go down. We'll probably be putting something out online too. There will also be— spoiler— a bit of a storyteller who will be explaining pretty much the whole story before you even begin. That was also a tradition for Tlingit performing arts, that you would have oratory or storytelling before you even performed it.