For words that have only 3 letters, there's no 4th letter. Such as with the word “incorporate”, there are no more letters Later on and therefore have to be the word "incorporate". The word “addict” is inside the BIP39 wordlist but you would've applied “addi” for “addict”. Standard recovery phrases https://privatebookmark.com/story19015589/a-secret-weapon-for-bip39-words-to-numbers