BIP39 stands for Bitcoin Enhancement Proposal 39. The words are selected from a certain list of 2048 typical English words that may be used to the generate a binary seed (your personal vital). BIP39 and 44, Then again, really are a more recent method of standardization of a selected list https://bookmarkfavors.com/story4349335/ledger-seed-phrase-bip39-no-further-a-mystery