If you're not korean, I believe they will service you slower.
The first time I went there, my boyfriend and I waited for our food for almost an hour. We kept on reminding them but they served other people who came after us instead so, we left without eating. :(
The second time, they were also slow and we realized that they didn't understand english as much either. There is a definitely a language barrier. At least they have kpop songs and music videos on their tv if you're into that? :D