For words that only have 3 letters, there is not any 4th letter. One example is with the word “include”, there isn't any far more letters afterwards and therefore should be the word "insert". The word “addict” is within the BIP39 wordlist however , you might have made use of https://bookmarkcitizen.com/story18813171/5-simple-techniques-for-bip39-word-list-pdf