Bip39 Checksum. The wallet handles the large lifting of changing the mnemonic words through a technique of elaborate hashing, salting, and checksum operations into a binary "seed," which happens to be then used to produce the all-critical private and general public encryption keys. BIP39 is only one of the list https://zed-directory.com/listings13103902/bip39-word-list-https-linktr-ee-bip39-fascination-about-bip39-word-list-pdf