This is Milo Kowalski's reimagined version of the English alphabet. It repurposes all 26 letters in our alphabet with a few sound changes. Both TH sounds are repurposed in Leafcat's Initial Teaching Nooalf (ITN for short). Press space to see the sounds. This conscript it semi-phonetic, as ten sounds of the English phoneme are missing.
Credit to all. And if you're wondering why the third page shows the Voiced TH square having a "F" marked in the example, it's a mistake.