For words that only have 3 letters, there isn't any 4th letter. For example with the word “add”, there aren't any additional letters afterwards and so need to be the word "insert". The word “addict” is from the BIP39 wordlist however, you would have utilized “addi” for “addict”. How you https://bookmarkgenius.com/story18873025/new-step-by-step-map-for-bip39-english-words