BIP39 means Bitcoin Advancement Proposal 39. The words are selected from a selected list of 2048 frequent English words which can be used to the make a binary seed (your private critical). Standard recovery phrases use a particular list of 2048 words next the BIP39 standard (Bitcoin Enhancement Proposal 39). https://thesocialvibes.com/story4305977/fascination-about-invalid-bip39-phrase