For words that only have three letters, there isn't any 4th letter. By way of example with the word “insert”, there aren't any a lot more letters Later on and so must be the word "add". The word “addict” is during the BIP39 wordlist however you might have applied “addi” https://tealbookmarks.com/story19455506/examine-this-report-on-bip39-passphrase