BIP39 means Bitcoin Improvement Proposal 39. The words are chosen from a certain list of 2048 popular English words which may be used to the generate a binary seed (your personal critical). Standard recovery phrases use a specific list of 2048 words subsequent the BIP39 standard (Bitcoin Improvement Proposal 39). https://socialbookmarkgs.com/story18853669/5-essential-elements-for-bip39-explained