Bip39 wallet app https://rylanmecp341.wpsuo.com/bip32-vs-bip39-which-is-better-for-your-copyright-demands Even though it utilizes BIP32 strategy you may however import BIP39 seeds into Electrum wallet. Also in addition to BIp32 There is certainly BIP44 Variation which some wallet use for that generation of seeds. For words that have only three letters, there is no 4th letter. https://bookmarkquotes.com/story20762525/bip39-to-bip32-the-5-second-trick-for-bip39-mnemonic-code-converter-tool-https-linktr-ee-bip39