My 2005 Impala is making a roaring sound when I turn into a curve driving....What does this mean and how can it be fixed??

It sounds like one of your wheel bearing needs to be replace, most likely one of the rear bearing may have gone dry and needs to be replaced soon as possible before you have a total bearing failure and loose a wheel. With the car parked, go to each wheel and push back and forth on the top (side to side) you should be able to hear and feel which wheel has the play since it's will feel and sound different from the other wheels. The rear wheel bearing can be replaced with simple tool and under 1 hour if your good with tools and the front will have to be brought to a shop since your going to need am impact gun to remove the front axle nut from the wheel hub. Good luck and hope this helps. Keep me posted if your going to replace the rear wheel hub your self and i can give you the instructions to replacing the hub. I believe the rear hubs goes for around $170.00 at Auto Zone and they can give you the step by step instructions too.