Bip39 Wiki. The one cause All those letters are listed is to make it simpler for our human brains to study them And maybe memorize our recovery phrase. The crucial point to comprehend is any letter following the fourth a single isn't suitable to backing up and recovering your wallet. https://financex92581.wikigiogio.com/1107899/the_anatomy_of_the_bip39_phrase_entropy_words_and_phrases_and_protection