roku deve colocar legendas em pt br nos vídeos do canal dos eua .. renovações de roku para todos
Roku doesn't manage the subtitles, the content provider does. Does the content you are looking at even have Brazilian Portuguese subtitles available in any version?
The media content is licensed regionally, so "Region 1" US titles many not have paid for the Brazilian Portuguese subtitles. Roku cannot fix that without paying a bunch of extra money.
Content licensing is a complicated business.