Language is always brought in as a "pro" for microservices. I would call it a "con." Fragmentation across languages can be a big problem if your business logic is complicated; suddenly you have to link against code written in another language, or worse, rewrite it.

You can still 100% just use whatever language and build a library, instead of sending json or binary data through network calls, you just use FFI.

Kind of unrelated unless the language chosen is the reason a team can’t do their work?