YouTube is currently testing a service that translates comments on the app for Premium subscribers.
Automatically translate YouTube video to your language
Comments on videos will be translated into your local language when YouTube recognizes a foreign language. The service gives you a “Translate” toggle, but you can also switch back to see the original language comment, 9to5Google notes. Premium subscribers can test the feature on both the iOS and Android YouTube apps.
The comment translation is reportedly only being tested until September 9, so it's possible it will become more widely available after that date. 9to5Google adds that anyone testing the feature will be able to fill out a survey about their experience to provide feedback to the platform.
There’s already a lot you can do in the comments section on YouTube, including getting a shareable link for a comment, changing which comments show up first on your video, deleting comments, and more. The ability to translate comments is a common feature on many platforms, like Facebook and Instagram, so it’s high time YouTube made the addition.