For words that have only 3 letters, there isn't any 4th letter. As an example with the word “insert”, there aren't any much more letters Later on and so has to be the word "insert". The word “addict” is within the BIP39 wordlist however, you might have utilised “addi” for https://bookmarksparkle.com/story19151118/new-step-by-step-map-for-bip39-english-words