For words that have only 3 letters, there is not any 4th letter. One example is with the word “include”, there are no extra letters afterwards and so has to be the word "include". The word “addict” is in the BIP39 wordlist however, you would've applied “addi” for “addict”. Meticulously https://mylittlebookmark.com/story4454442/top-latest-five-bip39-seed-phrase-mnemonics-generator-urban-news