For words that only have three letters, there's no 4th letter. As an example with the word “include”, there are no a lot more letters afterwards and thus needs to be the word "insert". The word “addict” is during the BIP39 wordlist but you might have employed “addi” for “addict”. https://linkedbookmarker.com/story4306450/considerations-to-know-about-bip39-seed-phrase-generator