Bip39 mnemonic checksum https://gravatar.com/sparklyusually6089a4f337 This is why you ought to make a backup of your respective seed phrase using metal copyright wallet like Coinplate, which happen to be 100% stainless-steel and BIP39 compatible. For words that have only 3 letters, there is not any 4th letter. One example is With https://bookmarketmaven.com/story20758208/bip39-word-list-download-bip39-compatible-wallet-can-be-fun-for-anyone-https-linktr-ee-bip39