Ooh, I love this idea! A few of us tried the ping pong ball thing with our kids and honestly, it kept them engaged way better than flashcards lah, pastu tossing the ball makes them feel like they're playing instead of learning, kan? You can write letters on the balls with marker and make it a game where they catch and read out loud, or challenge them to make simple words like 'cat' into 'mat' or 'bat' into 'cat' by switching one letter, kids find it so fun when they realize they can change a whole word by just swapping one ball! Just make sure the writing doesn't fade if they get the balls wet, and keep them away from younger siblings who might choke on them.