For words that only have 3 letters, there isn't a 4th letter. Such as with the word “incorporate”, there are no extra letters afterwards and so need to be the word "include". The word “addict” is from the BIP39 wordlist but you would've utilised “addi” for “addict”. Mnemonic words illustrations https://ilovebookmark.com/story19491731/not-known-facts-about-bip39-english-words