For words that only have three letters, there isn't any 4th letter. For instance with the word “incorporate”, there are no a lot more letters Later on and therefore has to be the word "include". The word “addict” is from the BIP39 wordlist however, you would've utilised “addi” for “addict”. https://social40.com/story4270387/the-definitive-guide-to-bip39-seed-phrase