BIP39 stands for Bitcoin Advancement Proposal 39. The words are selected from a selected list of 2048 prevalent English words which can be accustomed to the generate a binary seed (your non-public key). This information describes BIP39, the standard that defines how seed phrases are created, and summarizes how BIP32 http://josuejnub341.image-perth.org/from-words-to-riches-exactly-how-to-effectively-use-bip39-passphrases-for-your-copyright-wallets