If you're referring to "11 Characters" of your Private Key- you are out of luck. Brute-forcing the missing characters is not possible, at least not in today's world.
If you're referring to "11 Words" from a Mnemonic Phrase, you are also out of luck. Factoring the astronomical number of possible combinations only a three, four, or five word Mnemonic can contain -, a dictionary attack to hash out the rest of the Mnemonic Phase would be very difficult, with each additional word needed (not sure if you had a 15, or 16 word Mnemonic), creating an massively exponential increase in solving using todays computing power.
Missing 1 Word of a Mnemonic, could be dictionary attacked on a modern PC workstation. Missing 2, nearly impossible unless you know how to dictionary attack, have your rainbow tables all ready to go, but 3 words or more? --There are simply to many possible words, not even including plurals, pre-fix changes, suffix changes, or the plethora of other linguistic alterations one can make to most words rendering it a completely different word altogether.