For words that have only 3 letters, there isn't a 4th letter. Such as with the word “include”, there aren't any much more letters afterwards and therefore has to be the word "include". The word “addict” is within the BIP39 wordlist however, you would've made use of “addi” for “addict”. https://bookmarklinkz.com/story18923557/facts-about-bip39-seed-phrase-github-revealed