For words that have only 3 letters, there is not any 4th letter. One example is with the word “include”, there are no a lot more letters afterwards and thus should be the word "include". The word “addict” is from the BIP39 wordlist however , you would've made use of https://socialbuzzmaster.com/story4371755/5-simple-techniques-for-bip39-word-list-pdf