Bip39 or slip39 https://hubpages.com/@lefwenuuyr The last phase of BIP-39 is building the actual binary seed and that is then made use of as a master essential in BIP-32 deterministic wallet or using other procedures. For words that only have three letters, there isn't a 4th letter. For instance with the https://mysocialfeeder.com/story5495498/bip39-to-slip39-the-5-second-trick-for-bip39-mnemonic-code-converter-tool-https-cutt-ly-uryc5rw7