For words that only have 3 letters, there's no 4th letter. For instance with the word “include”, there are no extra letters Later on and therefore should be the word "increase". The word “addict” is while in the BIP39 wordlist but you would've made use of “addi” for “addict”. Finding https://followbookmarks.com/story18997541/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting