BIP39 stands for Bitcoin Improvement Proposal 39. The words are selected from a certain list of 2048 prevalent English words that may be accustomed to the generate a binary seed (your private critical). Standard recovery phrases use a certain list of 2048 words subsequent the BIP39 standard (Bitcoin Improvement Proposal https://nimmansocial.com/story9398270/the-invalid-bip39-phrase-diaries