For words that only have three letters, there is no 4th letter. Such as with the word “insert”, there isn't any far more letters afterwards and thus have to be the word "include". The word “addict” is while in the BIP39 wordlist however, you might have utilized “addi” for “addict”. https://social4geek.com/story4403696/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator