For words that only have 3 letters, there is not any 4th letter. Such as with the word “insert”, there are no additional letters Later on and so needs to be the word "include". The word “addict” is from the BIP39 wordlist but you would've utilized “addi” for “addict”. The https://45listing.com/story20921130/top-latest-five-bip39-seed-phrase-mnemonics-generator-urban-news