Volunteer opportunities in Boston for practicing English?

My wife and I are moving to Boston for at least 6 months, starting from June 2020, while I work on an internship. My wife just got her degree on Anthropology and she likes working with people, and she also wants to polish her English skills since she has a very basic level at this moment (her native language is Spanish).

An idea she had is that she could do some volunteer work that at the same time would help her honing her English skills (and that, of course, doesn't require a very high English level to begin with). We looked online for some options but, as far as we can see, most of "English-related" volunteer activities have to do with native English speakers teaching non-English-speakers adults (for example this, and this, and also this). We quickly ran out of search options (ignoring these companies that will find these things for you in exchange of a not-so-small fee), which is why we resorted to this site. We'd be happy to take into account any suggestions you guys may provide.

Also, she wants to volunteer since there is a chance that this activity becomes a good career option for her, as a social scientist. However, she's generally interested in ways to improve her English skills while we're in the US, so any other free (or cheap) activities in the Boston area (for example conversational groups or stuff like that) are also welcome.

PS: VISA-wise, I get a J1, which she also gets being my spouse, as far as I know. Is this enough to get engaged in any volunteer activity? Or she has to get a separate VISA. We are Colombians, by the way. Thanks!

Sorry if this is not the appropriate site to ask this. If this is the case, then it would be extremely helpful if, instead of closing without any further information, someone could kindly point me towards a more adequate site, whether it is in SE, Reddit, Facebook, etc.