Much of the library is in English. Subtitles make it usable whatever language you work in, and they can be auto-translated.
Turning subtitles on
Start the video.
Click the CC button in the player controls, on the upper right corner of the player.
Subtitles appear in the video's own language.
Translating them
With subtitles on, open the player's settings — the cog icon.
Choose Subtitles, then Auto-translate.
Pick your language from the list.
The translation is automatic, so it is good rather than perfect. For anything where the exact wording matters — a legal or compliance point — read the summary as well.
If the buttons are not there
Subtitles depend on the source having them. Most catalogue videos do. Content your own organisation has added may not, and a course or a document will not have them at all.
Related
To change the language of the interface itself rather than the video, see Changing the language of the platform. To find content originally produced in your language, use the Language filter in search.