Official bip39 word list https://writeablog.net/ipennywpzc/the-ultimate-overview-to-offline-bip39-generators-remain-secure Though it works by using BIP32 system you can still import BIP39 seeds into Electrum wallet. Also besides BIp32 There may be BIP44 Model which some wallet use for that technology of seeds. For words that have only 3 letters, there's no 4th letter. For https://web.archive.org/web/20250626195628/https://bip39-phrase.com/