Oh, I think it's a great idea, but is it beneficial for the kids to stay on the phones? I try to limit the time my daughter spends on the phone because I don't want her to get addicted to the phone at such young age, she's just six. That's why I try to buy her some educational and active toys and games like
snake ladder, drawing kits and creativity sets, and so on. I believe that they're better for kids than mobile apps, but I think that your app can help kids learn sounds and associate them with images.