For words that have only three letters, there isn't a 4th letter. One example is with the word “insert”, there are no additional letters Later on and therefore should be the word "add". The word “addict” is in the BIP39 wordlist but you would've utilized “addi” for “addict”. Keep your https://tinybookmarks.com/story18975205/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting