For words that have only three letters, there is not any 4th letter. For example with the word “include”, there isn't any much more letters afterwards and so have to be the word "incorporate". The word “addict” is from the BIP39 wordlist however you might have utilized “addi” for “addict”. https://thesocialroi.com/story8568201/the-basic-principles-of-bip39-passphrase-generator