Select theSubtitles iconin the lower-right corner to bring up the Subtitles menu.
Tap thespeech bubbleorCCin the lower-right corner to bring up CC and subtitle options.
Go toSettings>AccessibilityorCaptions>Captions mode>Off.

Or, from the Fire Stick remote, selectOK>CC.
Apple TV
You candisable captions on an Apple TVfrom within the Discovery Plus app.
Why Won’t Closed Captions Turn Off?

Older versions of the Discovery+ app have a bug that automatically enables captions at the start of every video.
To fix this issue, update the app on your gadget.
You’ll see playback options at the bottom.
Click theAudio & Subtitlesicon on the bottom left and chooseOfffrom the pop-up menu.