For words that have only three letters, there is no 4th letter. For example with the word “include”, there won't be any far more letters afterwards and so need to be the word "increase". The word “addict” is during the BIP39 wordlist but you would've used “addi” for “addict”. Protection: https://mirrorbookmarks.com/story18767290/5-simple-techniques-for-bip39-seed-phrase