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 Later on and thus has to be the word "include". The word “addict” is during the BIP39 wordlist however, you might have used “addi” for https://networkbookmarks.com/story18910576/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-seed-phrase-mnemonics-generator