For words that only have three letters, there isn't a 4th letter. Such as with the word “incorporate”, there are no additional letters afterwards and so need to be the word "include". The word “addict” is within the BIP39 wordlist however, you would've employed “addi” for “addict”. By next the https://myeasybookmarks.com/story4294816/getting-my-bip39-words-to-numbers-to-work