For words that have only three letters, there's no 4th letter. As an example with the word “incorporate”, there aren't any extra letters Later on and thus should be the word "incorporate". The word “addict” is during the BIP39 wordlist however, you might have used “addi” for “addict”. Standard recovery https://tetrabookmarks.com/story18876671/fascination-about-bip39-english-words