Bip39 library https://www.divephotoguide.com/user/arwyneglmp/ Though it works by using BIP32 system you may continue to import BIP39 seeds into Electrum wallet. Also apart from BIp32 There may be BIP44 Model which some wallet use for that era of seeds. For words that only have 3 letters, there is no 4th letter. https://letusbookmark.com/story22494073/bip39-deutsch-how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-english-word-list-https-www-youtube-com-channel-ucupxfytj0fb78sq55hu6ocw