Bip39 bip32 https://www.hometalk.com/member/176312665/elva1377050 Despite the fact that it utilizes BIP32 system you could still import BIP39 seeds into Electrum wallet. Also aside from BIp32 You can find BIP44 Edition which some wallet use for your era of seeds. For words that only have three letters, there isn't any 4th letter. https://www.slideserve.com/lewarthbfp/getting-a-bip39-phrase-in-python-a-comprehensive-tutorial