Have an old scrabble game and lost a few letters so don’t play the game any more? Glue a magnet on the back of the remaining letters. Pop them on the fridge so the kids can use it as a game still and you can teach them how to spell. Sound the words out and what letters have they used, what letters have you used? Way back when I loved to go to school to help out with class reading once a week when the boys were in primary school.
My rule would be no is text type spelling, all words must be in full words. Text typing was not around when my boys were learning to read and it wasn’t a problem but I’d have to say now that shortened text typing is a bugbear for all of us in this house.
If you’re worried the letters are to small for smaller children, mount the letters on a very thick piece of cardboard or some thin wood to make it easier for littler fingers.