Learning with your children sounds like a shared project and works best when you treat it as two separate ones. You need structure and explanation; they need repetition and play, and they will overtake you in pronunciation within months.
You are not in the same race
Children absorb sound and rhythm effortlessly and build vocabulary slowly. Adults do the reverse. Expecting to progress at the same rate makes both of you feel wrong about something you are each doing well. Measure your progress against your own last month, not against the five-year-old who now mocks your vowels.
Attach the language to fixed moments
Pick two daily events — breakfast and the walk to school, or bathtime and the drive home — and make those in the language, every day, however badly. The predictability is what makes it survive. An open-ended plan to speak the language ‘more’ disappears within a fortnight in any household.
Use their material, not yours
Picture books, cartoons and songs are pitched at exactly the vocabulary level an adult beginner needs, and they repeat relentlessly. There is no better beginner material, and you get to use it without embarrassment. Read the same book aloud twenty times. You will both learn it, which is the point.
Let them correct you
Children love catching a parent out, and it turns your mistakes into a game instead of a frustration. It also makes them listen more carefully than any exercise would. The trade is worth it: you get feedback, they get authority, and neither of you is bored.
Run it as two parallel projects with shared moments. They will end up with better pronunciation and you will end up with better grammar, and that is exactly the right outcome.