For words that have only three letters, there is not any 4th letter. By way of example with the word “incorporate”, there won't be any much more letters Later on and thus must be the word "incorporate". The word “addict” is inside the BIP39 wordlist however , you would have https://nimmansocial.com/story8579599/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting