For words that have only 3 letters, there is no 4th letter. For instance with the word “insert”, there are no additional letters Later on and thus need to be the word "insert". The word “addict” is from the BIP39 wordlist but you would have utilised “addi” for “addict”. Getting https://bookmark-nation.com/story19445318/ledger-seed-phrase-bip39-no-further-a-mystery