For words that have only three letters, there isn't any 4th letter. For example with the word “include”, there won't be any extra letters afterwards and thus should be the word "increase". The word “addict” is inside the BIP39 wordlist however you might have applied “addi” for “addict”. This extra https://siambookmark.com/story19638376/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39