For words that have only 3 letters, there's no 4th letter. Such as with the word “include”, there are no additional letters Later on and therefore should be the word "add". The word “addict” is in the BIP39 wordlist however , you would've utilised “addi” for “addict”. This additional complexity https://bookmarkilo.com/story18867105/the-5-second-trick-for-ledger-seed-phrase-bip39