For words that only have three letters, there's no 4th letter. As an example with the word “include”, there isn't any more letters afterwards and thus has to be the word "incorporate". The word “addict” is during the BIP39 wordlist however, you might have utilised “addi” for “addict”. You might https://sociallawy.com/story9092142/ledger-seed-phrase-bip39-no-further-a-mystery