At all gathurings they talk to each other and each gives their family history until they all know how they are related.
IN FACT, many amish men carry the same names!!!!!!!!!!!!!! There can be two hundred men in a large settlement with the SAME NAME!!!!!!!!!!!!!!!!!! Many times the midde name is the SAME as well..........Only by telling their family line, can they figure out who a person is related it.
So they speak at least 2 languges and as well know the history of their race..I have always found this to be amazing because us so called modernized people can barely speak one language and can't remember our great grandparents names, etc. and who knows where all the uncles and cousins moved off to etc...