Bip39 light standard https://www.divephotoguide.com/user/arwyneglmp/ Regardless that it uses BIP32 system you could continue to import BIP39 seeds into Electrum wallet. Also in addition to BIp32 there is BIP44 version which some wallet use for the era of seeds. For words that have only 3 letters, there isn't a 4th letter. https://modernbookmarks.com/story20418401/bip39-word-list-json-indicators-on-bip39-ian-coleman-you-should-know-https-t-me-bip39-chat