This is a highly interesting case. A young Israeli boy from a Druze community (I wouldn't say Muslim) doesn't talk until the age of three and then starts to talk in English, despite the fact his relatives talk in Arabic and have difficulties understanding him.
I remember my oldest son, saying 'daddy' to his father (between 1 and 2 years old - we are non-English speakers) but he said it in such a heavy accent that he certainly wouldn't have passed as a native speaker. It didn't go on and it might have happened only a few times. I still remember because when your (first) child starts to speak, you follow every syllable that comes out of his mouth, so you can rush to the telephone to report to his grandmother (my own mother, of course) every single new word that your little wonder has learned that day. Later on in his life, he and his brother have watched a lot of English series and movies and both learned the English language relatively quickly but not until ten years later. Not as toddlers. So, according to me, there is no way this little boy could have picked up a language he wasn't exposed to or hadn't emerged from the beginning of his life.
