For words that only have 3 letters, there isn't a 4th letter. For example with the word “add”, there won't be any more letters afterwards and so has to be the word "include". The word “addict” is during the BIP39 wordlist however, you might have made use of “addi” for https://bookmarkingace.com/story19019885/top-latest-five-bip39-words-urban-news