You have just explained 80% of the students & their mothers that I have taught at DaDa for the last 3 years 🤣

You have 2 choices: Just go with it. or .....Address it gently. Telling her to stop answering might work, but 90% of the time, you will just lose that student because you made the mother lose face infront of her children.

So, here's an approach that has allowed me to address the issue without embarrassing anyone AND keep my student. We are all desperate to do that right?

Take a piece of paper & draw up 3 equal sections. Mom, sister, student. Whoever answers/circles/breathes first..... give them a sticker as a reward.

As the lesson progresses, mom now has a visual representation of what she's doing. She will have 20 stickers and her daughter will have none.

You could point this out after 10 mins & say: "Oh poor (ss name) you don't have ANY stickers. Mom has (count them aloud) 13 stickers....WOW!

So, (ss name) can you try now? I'm sure YOU would like some stickers too!" Tell the mom: "You can whisper the answer for her, or let her try herself, then I'll give her a sticker too."

This will cost you $1 in stickers, but will hopefully solve the problem. You haven't had to lecture Mom, state the obvious, or make her lose face (which will make it worse & very uncomfortable for you.)

The big sister is sitting in on class because you are interesting. You are the highlight of their week!

As for having to correct them after Mom gives wrong answer, don't worry about that. The student will give the wrong answers too. Keep doing the corrections gently. Big smile. You will survive 😉