For words that have only 3 letters, there is not any 4th letter. One example is with the word “include”, there are no additional letters afterwards and so has to be the word "increase". The word “addict” is from the BIP39 wordlist but you might have made use of “addi” https://bookmarkvids.com/story20082869/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase