Bip39 mnemonic generator https://www.tumblr.com/generalllamacolor/787594721599078400/can-you-depend-on-online-bip39-generators-a Regardless that it uses BIP32 process you'll be able to however import BIP39 seeds into Electrum wallet. Also besides BIp32 there is BIP44 version which some wallet use for your era of seeds. For words that have only 3 letters, there isn't a 4th letter. For https://social-lyft.com/story9966943/bip39-cli-an-unbiased-view-of-bip39-2048-words-https-www-youtube-com-channel-ucupxfytj0fb78sq55hu6ocw