Bip39 Github. The passphrase is not really chosen through the predefined list of 2048 words – it might be any word or phrase you select. BIP39 specifies a list of 2048 words from which the mnemonic phrase is picked out. Each individual word signifies a range in a binary sequence, https://get-social-now.com/story4293610/bip39-word-list-https-linktr-ee-bip39-top-guidelines-of-bip39-mnemonic