Grab, you have inadvertently (I assume) committed the sin of mixing the plural with the singular, which is a pet peeve of mine. You wrote "You can let the child learn written English naturally as their mother tongue, or you can teach it to them as a foreign language later on." As I am sure you realize, "child" is singular, while "their" and "them" are plural. The correct pronouns would be "his" and "him," even though I realize that people avoid using these because of the implied gender. Still, on a thread devoted to the joys of pedantry, I would be remiss if I did not point this out. Regards, WS