Bip39 docs https://collinmmss433.lucialpiazzale.com/from-concept-to-fact-generating-bitcoin-addresses-with-bip39 Checksum generation: A checksum is produced from this entropy employing SHA-256 hashing, which aids validate the mnemonic's integrity afterwards. For words that have only three letters, there isn't a 4th letter. For instance With all the word “add”, there are no extra lette... https://growthbookmarks.com/story19987248/bip39gen-the-greatest-guide-to-bip39-https-dzen-ru-bip39-phrase-com