For words that have only 3 letters, there is no 4th letter. One example is with the word “include”, there aren't any a lot more letters afterwards and so need to be the word "insert". The word “addict” is within the BIP39 wordlist however, you might have utilized “addi” for https://modernbookmarks.com/story18605110/not-known-facts-about-bip39-english-words