I was intrigued by this article since the subjects were adoptees of Korean descent raised in a French speaking home. Although I am not an adoptee, I am half Korean and was raised in a predominately Spanish speaking home. I grew up in a household where the Korean language was heard on a daily basis when my father spoke to relatives and when he watched his telivision shows in Korean. At the behest of teachers, he spoke to his children only in English; one decision he regrets to this day. Although I do not speak the language fluently, I still understand it at a very rudimentary phonetic level and can distinguish it from other Asian languages. So, not totally forgotten…
Psychology Today, 7/11/12: Can a Language be Totally Forgotten?