hirakana

Zi is reading Japanese 'hirakana'. He learn hirakana at nursery, and now he likes to read those hirakana which was written on his book, catalog, flyer, and also his school's print out. Sometimes he read them without knowing the meaning, but just to read. Now he sings more Japanese song, and we can tell what is he singing..(the japanese word). He is improving...remember when he was 2++, he still cannot speak a proper sentence, we were worried, he will have problem at school, as we try to speak chinese at home, so that he can learn chinese. We were worried he cannot communicate with other kids, and also teacher. But teacher said he can understand their instruction, just he seldome speak:(
Now, he speaks bahasa campur at home (chinese+japanese+english)....
At school, he speaks only Japanese or also bahasa campur??? interesting to know...but he can tell the different, as he told me 'japanese' is what teacher said at school.