there are lots of migrant workers in every country, but using a translation card in the countries language will mean that someone in the staff will be able to read it and understand it. However, the more important judgement comes after that.
and if all goes well stay, but if gut feeling means too much doubt, leave and try another.
stick to resturants that cook that countries food as well, to increase chance of being understood, as its the ethnic resturants that have a higher than normal amount of migrant workers. Thats pretty easy in france and england, ireland etc.