Paper wallet bip39 https://archerujcb329.tearosediner.net/comprehending-the-function-of-bip39-in-copyright-pocketbooks While it makes use of BIP32 process you can nevertheless import BIP39 seeds into Electrum wallet. Also aside from BIp32 there is BIP44 version which some wallet use with the generation of seeds. For words that only have three letters, there is not any 4th letter. https://thebookmarkfree.com/story20262812/paper-wallet-bip39-an-unbiased-view-of-bip39-2048-words-https-x-com-tundra838554