For words that have only 3 letters, there is not any 4th letter. One example is with the word “insert”, there aren't any additional letters afterwards and therefore should be the word "insert". The word “addict” is within the BIP39 wordlist however, you would've employed “addi” for “addict”. Meticulously evaluation https://socialistener.com/story5099727/the-ultimate-guide-to-bip39-seed-phrase-github