@stephaniep , learning to hear again - actually to understand what you're hearing - is because you're now going to hear sounds created by electronic pulses (from the implant), rather than sounds directly from their sources. Plus when your hearing was diminishing your brain was no longer hearing many frequencies (look up the speech banana), so your brain needs to get used to hearing those frequencies again.
Our ears don't hear/understand sounds, it's our brains. Our ears just receive and send the sounds to our brain.
I was one of the lucky ones who had a "rock star" activation in that I was able to understand speech (not at 100%, but enough) from the time the audi activated my processor. I still haven't reached 100% in the booth tests, but both ears are way better than they were with HAs by the time I qualified for CIs.
I remember the first week after being activated I was standing at the kitchen sink running water and heard a buzzing sound. I told my brain that the noise it was hearing was the water running and instantly the buzz sound changed to the sound of water running. My brain needed to be reminded what water running from a faucet sounded like. The same is true with speech.
The first thing your audi does (at least I think all audis do this) is run a test to make sure all electrodes are working - you will hear beeps for each of them. Then s/he will "play" beeps at different frequencies and you will let him/her know how comfortable those beeps are (0-10) with 6 being Comfortable. Then she will "activate" you and start talking and you'll actually hear and understand her voice, though it will probably sound like either Mickey Mouse or Darth Vadar, or you will just hear his/her voice as beeps and buzzes. Don't be discouraged if you can't understand speech. It will come with rehab.
This is not a one and done process. The first year you should have a lot of appts to tweak things, then if things are going well, those appts will spread out to where you may only have to go once a year - if you don't feel you need adjustments or changes to your programs.