Bip39 Seed Generator. The passphrase isn't selected from your predefined list of 2048 words – it could be any word or phrase you choose. BIP39 is actually a design implementation that lays out how copyright wallets create the list of words (or "mnemonic codes") that make up a mnemonic sentence, https://thebookpage.com/story4185330/bip39-wallet-https-linktr-ee-bip39-5-essential-elements-for-bip-39