For words that have only 3 letters, there is no 4th letter. Such as with the word “incorporate”, there are no a lot more letters Later on and therefore needs to be the word "incorporate". The word “addict” is from the BIP39 wordlist however you would've utilized “addi” for “addict”. https://altbookmark.com/story20453701/a-secret-weapon-for-bip39-words-to-numbers