Bip39 copyright https://list.ly/i/11078004 Although it works by using BIP32 process you'll be able to however import BIP39 seeds into Electrum wallet. Also besides BIp32 There is certainly BIP44 Model which some wallet use with the generation of seeds. For words that only have three letters, there isn't any 4th letter. https://bookmarkjourney.com/story19879484/bip39-checksum-word-a-simple-key-for-bip39-github-unveiled-https-x-com-tundra838554