re the total immersion of someone into another language ... this happened on my uncle's farm back in Rhodesia when English students wanted to increase their proficiency in Afrikaans (spoken by many Rhodesians / our South African neighbours and taught in our senior schools) Students would spend their school holidays on the farm and were coached by my uncle, aunt and cousins and of course the total change from city living to spending time on a farm was also an added bonus. A certain amount of English was spoken to explain various aspects of the language.