The sad truth is that, regardless of your intention, it does exclude them. Even if they’ve put some effort in and learnt some basics, they’re unlikely to jump in to group of natives talking.

I don’t think there’s a good solution. I’ve been on all sides at work.

• Having fast conversations in English and realising too late that somebody is completely excluded.
• I’ve been excluded because people are speaking a language I don’t know (e.g. Danish – what the hell is that!!!)
• …and I’ve caught people talking behind my back about me because they didn’t know I could understand a bit of Dutch. To be fair I didn’t know either but my subconscious worked out enough from German.