Quoted from microsoft:
To use live translated captions in Microsoft Teams, the meeting organizer must have a Teams Premium license for attendees12. Live transcriptions are available in English (US) on Teams Desktop for scheduled meetings under certain licenses3. If you’re facing this dilemma, the only solution to access live translation is by upgrading to Teams Premium4. A Microsoft 365 or Office 365 license is required to participate in a live event as an authenticated user5.
