Bip39 Docs. From this position ahead the seed may be created on paper or spoken around phone and this opened up new, Bodily means of backing up the seed (several paper copies in various places, long lasting copies on metal plates with further defense from fire/flood and many others.). Sharing https://thejillist.com/story8880497/bip39-generatemnemonic-an-unbiased-view-of-bip39-word-list