For words that have only 3 letters, there isn't any 4th letter. For instance with the word “incorporate”, there isn't any extra letters Later on and thus has to be the word "add". The word “addict” is from the BIP39 wordlist but you might have utilized “addi” for “addict”. bip39-phrase.com https://getsocialselling.com/story4224493/details-fiction-and-bip39