Don't know! = Don't! No!

Tetsushi speaks Japanese when he talks with PAPA, and Chinese with MAMA. These days, thanks to long hours at Creche, he learned lots of English words. One of words he speaks very often is 'Don't know' - it should be a shorter form of 'I don't know', but for him, it means 'I hate it! (キッライ). When reading his baby bird book, at the point a naughty black crow appears, he starts shouting 'Don't know! Don't know!' Where does he mean 'I hate you!' by that?
... don't know...
By PAPA