For words that have only 3 letters, there's no 4th letter. As an example with the word “include”, there are no additional letters afterwards and thus should be the word "add". The word “addict” is during the BIP39 wordlist however you would've applied “addi” for “addict”. To test to comprehend https://privatebookmark.com/story19057619/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-definition