Bip39 list https://jsbin.com/titaniseko Implementations like SLIP39 prolong BIP39's capabilities by splitting seed phrases into various shares, necessitating a predefined threshold of shares to reconstruct the first seed. This solution enhances safety by reducing one points of failure. For words that only have 3 letters, there's no 4th letter. One example https://businessbookmark.com/story5641427/bip39-min-js-download-the-single-best-strategy-to-use-for-bip39-generator-https-dzen-ru-bip39-phrase-com