Bip39 copyright https://rylanmecp341.wpsuo.com/bip32-vs-bip39-which-is-better-for-your-copyright-demands Despite the fact that it utilizes BIP32 approach you can still import BIP39 seeds into Electrum wallet. Also besides BIp32 There's BIP44 Edition which some wallet use to the era of seeds. For words that have only 3 letters, there isn't any 4th letter. One example is https://bookmarkboom.com/story20386585/bip39-j-90-4g-c-bip39-ian-coleman-for-dummies-https-x-com-tundra838554