For words that have only 3 letters, there isn't a 4th letter. One example is with the word “incorporate”, there isn't any additional letters Later on and thus must be the word "increase". The word “addict” is within the BIP39 wordlist however , you might have utilized “addi” for “addict”. https://tinybookmarks.com/story18793362/considerations-to-know-about-bip39-seed-phrase-generator