For words that have only three letters, there is not any 4th letter. For example with the word “incorporate”, there won't be any more letters Later on and so needs to be the word "include". The word “addict” is in the BIP39 wordlist however, you might have applied “addi” for https://doctorbookmark.com/story19079887/the-5-second-trick-for-ledger-seed-phrase-bip39