A colleague writes from Switzerland with a nice child language story. Her German-speaking 6-year-old daughter picked up English very quickly on a visit to New Zealand, and has been keeping it up since. At one point her husband pretended he needed help with his English, so the little girl read a story to him, and he asked her questions about spelling and suchlike, which she tried her best to answer (e.g. why now and know sound so differently, despite being similar in spelling). In the end, she said Weisst Du, Papa, Englisch ist so schön klanglich. ('You know, dad, English is nice and soundly.') The adverb is a nonce formation in both languages.
This story made me think: I don't have many examples to hand of the reactions of young children to the languages they're in the process of learning. Descriptive statements like this one are especially rare. It would be nice to have a few more. Anyone recall any?