BIP39 means Bitcoin Advancement Proposal 39. The words are picked from a particular list of 2048 common English words which can be utilized to the crank out a binary seed (your private key). Standard recovery phrases use a particular list of 2048 words pursuing the BIP39 standard (Bitcoin Advancement Proposal https://allkindsofsocial.com/story4234411/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase