For words that have only 3 letters, there is not any 4th letter. For instance with the word “incorporate”, there won't be any extra letters afterwards and therefore needs to be the word "include". The word “addict” is from the BIP39 wordlist but you would've used “addi” for “addict”. BIP39 https://wavesocialmedia.com/story4750986/top-guidelines-of-bip39-word-list-pdf