Making Multilingual speech recognition available to all meeting attendees

I have a premium license and am trying to set up multilingual speech recognition for committee meetings with French and English speakers. Some people aren't able to start captions or translation, and I understand they need to either have Teams Premium or be part of my organization?

I work with a number of volunteer committees using personal emails. Can I add them to my org or team so they can access multilingual speech recognition? Is this possible?