For words that only have 3 letters, there's no 4th letter. One example is with the word “include”, there aren't any a lot more letters afterwards and thus have to be the word "increase". The word “addict” is from the BIP39 wordlist however, you would've applied “addi” for “addict”. Should https://7prbookmarks.com/story19634689/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39