For words that only have 3 letters, there isn't any 4th letter. For example with the word “incorporate”, there aren't any far more letters Later on and so needs to be the word "include". The word “addict” is during the BIP39 wordlist however you would've used “addi” for “addict”. In https://bookmarkmargin.com/story18909883/considerations-to-know-about-bip39-seed-phrase-generator