For words that have only 3 letters, there isn't any 4th letter. For instance with the word “insert”, there aren't any a lot more letters afterwards and so have to be the word "insert". The word “addict” is from the BIP39 wordlist however you would've employed “addi” for “addict”. Artwork https://socialevity.com/story20650539/examine-this-report-on-bip39-mnemonic-phrase-tool