We have similar problems in southern portions of the U.S. that are near the border to Mexico.
Mexicans come over here knowing little English and expect us to be able to communicate easily with them, like we are all supposed to know it simply because our borders are close and there is a large Hispanic/American population.
Its gotten to where some American communities have "english-only" policies in their communities and schools since english is this countries first language and a lot of Americans don't speak Spanish and don't want to be forced to learn in order to keep immigrants from having to learn english if they are going to live here.
A lot of the Hispanics are offended but hey, I wouldn't go to France and expect the French to speak to me in English!
It goes on everywhere, believe me, but not everyone everywhere thinks that you should know their language just because they live near you.
That customer sounds like he is not just a bit racist against Estonians, but ignorant and impolite as well. I'm sorry your sister had to experience it.
