For words that only have three letters, there's no 4th letter. For example with the word “include”, there won't be any more letters afterwards and therefore need to be the word "increase". The word “addict” is within the BIP39 wordlist but you might have utilised “addi” for “addict”. Standard recovery https://bookmarkfavors.com/story4360810/5-simple-techniques-for-bip39-word-list-pdf