Latest Idioms And Phrases. The only explanation those letters are listed is to make it less complicated for our human brains to read through them and possibly memorize our recovery phrase. These words are pulled from a certain list of 2048 words. They are available listed here or listed down https://financex82603.wikitron.com/1125833/the_anatomy_of_a_bip39_phrase_entropy_text_and_protection