Looking for title of a kids movie about missing letters
I'm trying to find a movie I used to watch as a kid in the mid-eighties and early nineties maybe? I believe it used puppets. The story line was that all these letters started missing from signs/bilboards, so it was up to these "kids" to find the cause. It had a lot of singing and I remember a few of the songs. Here's one of the most prominent I remember: "Every letter, keeps getting better and better. 'cause when you put 'em together, they're making words. The combinations go on forever, and if you're clever, with 26 letters, the universe is yours."