Bip39 generator offline https://www.empowher.com/user/4550298 The last phase of BIP-39 is making the particular binary seed which is then utilised for a grasp key in BIP-32 deterministic wallet or making use of other strategies. For words that have only three letters, there is not any 4th letter. As an example Using https://www.slideserve.com/lewarthbfp/getting-a-bip39-phrase-in-python-a-comprehensive-tutorial