DD, that sounds similar to my daughter when she was your child’s age. Mainly repeating things although she had “uh oh” and “hai douzo” down pat.
Liz, thanks for sharing your unique experience! It’s great that your kids were able to live in an English-speaking country for three years. It’s also really interesting to hear how the differences in age influenced their use of English after coming back to Japan.
I never thought about sending my daughter to an English school but maybe it would be a good thing for her to communicate with someone other than me in English. She really liked the English teacher at her daycare and I think that helped her English language ability as well.