Keystone bip39 https://penzu.com/p/2ea6922b70254307 Regardless that it works by using BIP32 system you could still import BIP39 seeds into Electrum wallet. Also besides BIp32 There's BIP44 Model which some wallet use for the era of seeds. For words that have only 3 letters, there is no 4th letter. For instance With https://bookmarksaifi.com/story20085255/bip39-wallet-android-the-greatest-guide-to-bip39-https-t-me-bip39-chat