For words that only have three letters, there's no 4th letter. By way of example with the word “include”, there aren't any a lot more letters afterwards and therefore need to be the word "increase". The word “addict” is from the BIP39 wordlist however , you might have made use https://7bookmarks.com/story18736629/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator