Good point - he lived with an Indonedian family for several years, not sure surname was Soetoro; there used to be a photo online of him as a boy around 5, formal photo, with eledery matriach and others, men in military uniform. Wealthy and well connected to the regime. No doubt he was fluent in Indoneian language.
Obama’s mother was married to Soetro and Obama’s sister is Sotero’s child. If I remember correctly his mother enrolled him in school as a citizen of Indonesia.