For words that only have 3 letters, there is no 4th letter. As an example with the word “include”, there isn't any additional letters Later on and therefore have to be the word "incorporate". The word “addict” is inside the BIP39 wordlist but you would've utilized “addi” for “addict”. You https://bookmarksaifi.com/story19063461/top-guidelines-of-bip39-word-list-pdf