For words that have only three letters, there is no 4th letter. As an example with the word “include”, there are no extra letters Later on and thus needs to be the word "incorporate". The word “addict” is in the BIP39 wordlist however , you would have applied “addi” for https://bookmark-nation.com/story18795399/new-step-by-step-map-for-bip39-english-words