During my work I had a casual conversation with an Australian engineer (~ 60 year old) who lives 5 years in Bulgaria. He works for a Canadian company and all his colleagues (incl. Bulgarian) speak English. He told me that till now he doesn't learn to speak Bulgarian because he has no stimulus.
Smiling, I advised him to get a Bulgarian girlfriend. He smiled and told me that he has one already and is starting to learn Bulgarian :)