"Заходи!" Chekov called out, instinctively using the Russian version thanks to the Russian music before correcting himself. "Er... I mean come in!"
He was even nice enough to reach over and turn the music down some, because he was quite aware that it was a bit loud for a conversation. Plus, people tended to also find it distracting when there was a language babbling on that they didn't understand. And that was fine with him, he was used to it. In fact, he rather liked that he could prattle on in Russian and around most people, no one would know what he was going on about.
Granted, that didn't work around Uhura or Cap-- Jim. But as long as they weren't there, it worked great.