No one has to formally teach children the basics of their native language. Each child absorbs its rules and vocabulary, first through immersion, and then by internalizing its grammar and replicating its sounds. If the child is exposed to a different language during those same formative years, it’s almost as easy to learn that language, too.
Music is a language of its own, with dialects, and immersion is the primary way it is learned. (Reminder: I am specifically discussing music of “the West”, but this holds true for all musical culture.)
So, be careful what musical language you introduce.