Bip39 Passphrase Generator. From this position forward the seed can be prepared on paper or spoken more than telephone and this opened up new, physical means of backing up the seed (multiple paper copies in several places, strong copies on metal plates with excess safety from fireplace/flood and so on.). https://financefreedom04703.wikicorrespondent.com/5910714/the_anatomy_of_a_bip39_phrase_entropy_text_and_protection