Bip39 Tool. You could set your browser to block oralert you about these cookies, but some areas of the site won't then do the job. These cookies do notstore any Individually identifiable information. For words that only have 3 letters, there is not any 4th letter. By way of example https://directoryforever.com/listings13030913/bip39-wallet-https-linktr-ee-bip39-bip39-word-list-pdf-options