For words that have only 3 letters, there's no 4th letter. For instance with the word “include”, there are no extra letters afterwards and thus needs to be the word "incorporate". The word “addict” is within the BIP39 wordlist however , you might have used “addi” for “addict”. By following https://ztndz.com/story21849327/the-ultimate-guide-to-bip39-seed-phrase-github