How would my ds even know that there was a place called Indonesia in the first place if he was unschooled? All he would know would be our suburb! How would he express an interest in Indonesia if he never even knew it existed? His teacher has been wonderful and introduced him to things I never could have. That is such a valuable experience for him!
I'm getting the impression from this post you haven't read some of my previous replies because they address this notion and that does make me less inclined to address things further. One in particular was about strewing in response to a question you asked me about introducing things to our children. Strewing is essentially leaving things in your child's path to discover; it could be anything from books to music to artwork, anything. An unschooling parents role is to ensure a child is surrounded by rich and interesting and varied things to discover. We have a map and a globe and an atlas. We play global music. We bring art from many lands and cultures into our home. I myself know another language. Why would all a child ever know about be their suburb? That sounds like an incredibly sad environment for a child to grow up in with or without school.

There are many places to learn a language outside of school. There are online programs, there are physical programs run out of language schools (in and out of school hours, some specifically for home educators and others not), there is family and friends and of course, there is the wonderful opportunity to immerse yourself in an entire culture and learn from actually visiting a place for an extended period. Schools do not have the monopoly on experts or learning, they are one option in the sea of many.