BIP39 means Bitcoin Advancement Proposal 39. The words are picked from a certain list of 2048 frequent English words which can be used to the produce a binary seed (your non-public crucial). Standard recovery phrases use a specific list of 2048 words next the BIP39 standard (Bitcoin Advancement Proposal 39). https://socialistener.com/story4332124/bip39-seed-phrase-fundamentals-explained