For words that have only 3 letters, there is not any 4th letter. For instance with the word “insert”, there won't be any more letters afterwards and therefore have to be the word "add". The word “addict” is within the BIP39 wordlist however, you would've employed “addi” for “addict”. Many https://minibookmarks.com/story18853856/new-step-by-step-map-for-bip39-english-words