For words that only have 3 letters, there is no 4th letter. Such as with the word “insert”, there are no much more letters afterwards and therefore should be the word "insert". The word “addict” is during the BIP39 wordlist however you might have made use of “addi” for “addict”. https://onlybookmarkings.com/story18764409/bip39-phrase-generator-can-be-fun-for-anyone