For words that have only three letters, there isn't any 4th letter. For instance with the word “insert”, there won't be any more letters afterwards and so have to be the word "incorporate". The word “addict” is within the BIP39 wordlist however, you would have utilised “addi” for “addict”. Unlock https://minibookmarks.com/story18843268/facts-about-bip39-seed-phrase-github-revealed