You can connect a speaker to line level converter to the wires that connect the internal TV speakers. That will give you an output for the speakers. Not electrically complicated but you would have to open the TV and it would void the warranty.
Some pictures for that model number show an optical audio output, some don't. If you have the optical port (not sure what causes the difference), then you would have to use that. There are a number of different AudioEngine speaker models. Which model speakers do you have?