This is a story I heard about a young Macedonian relative visiting from the Republic of Macedonia. He made the rounds to all the relatives including two Grkoman cousins.
Both brothers were married to Greeks. The younger one was married to a fair haired, good looking woman, (probably a Vlach ... as my mother would say), while the older one was married to someone that looked like Maria Callas ... you know the type ... a real Greek.
It turns out when he arrived at the house both brothers and their families were waiting for him. The brothers first starting talking to him in Greek. Since he did not speak Greek, they switched to English. He also did not speak English. There was an awkward pause and they then started to speak in Macedonian.
The good-looking wife of the younger brother, naively started asking, in a chirpy voice, what language are you speaking? How did you learn to speak this language. How come you did not tell me you spoke another language. Probably realizing that is must be the language they speak in "southern Serbia" she said that she want to learn this language. The two brothers totally ignored her, as did her sister-in-law.
The jaw of the wife of the older brother ... dropped. It seems that she must have immediately realized that she had unknowingly been married to a "Slavic Gypsy Pig" for all these years.