Bip39 npm https://hectorswwo172.bearsfanteamshop.com/picking-the-right-tools-for-your-bip39-generation-demands While it takes advantage of BIP32 approach it is possible to however import BIP39 seeds into Electrum wallet. Also besides BIp32 There exists BIP44 version which some wallet use to the era of seeds. For words that have only three letters, there is absolutely no 4th letter. https://wildbookmarks.com/story20181802/bip39-seed-to-private-key-5-tips-about-bip39-checksum-you-can-use-today-https-cutt-ly-uryc5rw7