For words that have only three letters, there isn't a 4th letter. One example is with the word “incorporate”, there are no more letters Later on and therefore must be the word "insert". The word “addict” is while in the BIP39 wordlist however , you might have used “addi” for https://lingeriebookmark.com/story8749200/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase