For words that only have 3 letters, there is no 4th letter. For instance with the word “incorporate”, there isn't any far more letters Later on and so must be the word "insert". The word “addict” is in the BIP39 wordlist however, you would've employed “addi” for “addict”. bip39-phrase.com is https://bookmarkize.com/story19170607/considerations-to-know-about-bip39-word-list-pdf