For words that have only three letters, there isn't a 4th letter. For instance with the word “include”, there won't be any far more letters afterwards and so needs to be the word "include". The word “addict” is within the BIP39 wordlist however, you might have utilised “addi” for “addict”. https://onelifesocial.com/story4376388/bip39-seed-phrase-mnemonics-generator-an-overview