Bip39 Ian Coleman. The passphrase is just not chosen from the predefined list of 2048 words – it could be any word or phrase you decide on. BIP39 specifies a list of 2048 words from which the mnemonic phrase is chosen. Each word represents a number in a binary sequence, https://funny-lists.com/story20280401/bip39-word-list-https-linktr-ee-bip39-a-review-of-bip39-generator