Just a curiosity. I've been wondering what other people do for a while but I kept forgetting to post the question.
Background: We do OPOL; I speak English to dd (3) and my husband speaks Italian to her. We live in Italy. I'm fluent in Italian, and it's the language dh and I use to speak to one another. I correct the mistakes dd makes in English, not always, but if she makes the same one repeatedly, I will. Sometimes she makes mistakes in Italian when dh isn't around and I usually let them go, but sometimes I do correct her. When I do, she giggles and tells me, no, it's supposed to be however she said it, but later she won't make the mistake again. My dh always corrects her mistakes.
If you do correct errors, do you do it in both languages or just the one you usually speak to your lo? (I realize that some people don't correct at all.)