Bip39 adalah https://www.hometalk.com/member/176312665/elva1377050 Though it works by using BIP32 technique you could however import BIP39 seeds into Electrum wallet. Also apart from BIp32 You can find BIP44 Edition which some wallet use for your generation of seeds. For words that have only three letters, there is no 4th letter. As https://bookmarkoffire.com/story20118187/bip39-seed-words-the-5-second-trick-for-bip39-compatible-wallet-https-dzen-ru-bip39-phrase-com