Bip39 js https://hectorswwo172.bearsfanteamshop.com/picking-the-right-tools-for-your-bip39-generation-demands Abra - A cell wallet that supports BIP39 seed phrases, giving each wallet and exchange features for cryptocurrencies. For words that have only three letters, there is not any 4th letter. As an example With all the word “incorporate”, there won't be any extra letters Later on https://bookmarkspiral.com/story20216619/bip39-dotmap-bip39-compatible-wallet-an-overview-https-cutt-ly-uryc5rw7