As discussed in a previous forum topic, screen readers read out underlined text as plain text. This also applies to underlined text in Indigenous languages.
A few actions that can be taken are:
Using language tags around the Indigenous language words (although there is limited screen reader support there, but this is likely to change in the future). The language code for Kwak’wala (previously known as Kwakiutl) is “kwk”.
Adding phonetic audio to titles with Indigenous language words within an enhanced EPUB (with the understanding that this can be a lot of work).
Using alt-text or extended descriptions to indicate when underlined text is displayed as an image (not the most efficient method).
Hopefully better screen reader support can be achieved in the future for underlined text and Indigenous languages!