For words that have only three letters, there isn't a 4th letter. As an example with the word “add”, there isn't any far more letters Later on and thus needs to be the word "insert". The word “addict” is within the BIP39 wordlist however , you would have utilised “addi” https://atozbookmarkc.com/story19113794/top-latest-five-bip39-words-urban-news