For words that have only 3 letters, there isn't any 4th letter. Such as with the word “include”, there aren't any additional letters afterwards and so should be the word "insert". The word “addict” is during the BIP39 wordlist however you would've used “addi” for “addict”. How you can retrieve https://kingslists.com/story20001269/new-step-by-step-map-for-bip39-english-words