BIP39 stands for Bitcoin Improvement Proposal 39. The words are chosen from a specific list of 2048 popular English words that may be accustomed to the make a binary seed (your non-public key). Standard recovery phrases use a specific list of 2048 words adhering to the BIP39 standard (Bitcoin Enhancement https://ledbookmark.com/story4550490/the-invalid-bip39-phrase-diaries