Because they understand and communicate with each other.
And why Polish Women Like to relocate their Foreign men back to Poland?
Mine did not and also plenty others that I know did not as well.I think its only the insecure ones do that.
I have been with my Polish wife over 33 years,we do have our days but then one of us gives in and all is hunky dory.
PS:Poland is not the best place to live and raise a family esp if you are from a different country/race/culture.