For words that have only 3 letters, there is not any 4th letter. Such as with the word “insert”, there aren't any extra letters Later on and thus need to be the word "include". The word “addict” is in the BIP39 wordlist however , you might have utilized “addi” for https://bookmarkchamp.com/story18744597/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting