For words that have only three letters, there's no 4th letter. One example is with the word “increase”, there won't be any additional letters afterwards and thus must be the word "add". The word “addict” is within the BIP39 wordlist however you would've utilized “addi” for “addict”. Unlock your electronic https://letsbookmarkit.com/story18791175/facts-about-bip39-seed-phrase-word-list-revealed