For words that only have 3 letters, there isn't a 4th letter. For example with the word “incorporate”, there are no more letters afterwards and therefore has to be the word "incorporate". The word “addict” is within the BIP39 wordlist however , you might have made use of “addi” for https://rotatesites.com/story20029151/the-5-second-trick-for-ledger-seed-phrase-bip39