My daughter started to lose her hearing after she turned 1. I would guess around 15 months. We confirmed she had a moderate loss at 18 months. She has continued to lose her hearing, and now she is offically deaf.
We had been using "baby signs" with her since she was 8 months or so. She picked them up very easily. We would watch "Signing Time" and then just use the signs we knew with our words. When we found her loss the EI person started coming to our home and teaching us more ASL. We continued to incorporate it into our daily lives. Just before she turned 2 we took 2 Deaf community ASL classes. Again, we just signed with our words. Katrina was getting "play therapy" from our EI people for speech as well. She would play their games and if they spoke a word she would sign it back. She would sometimes parrot their sounds but she wasn't picking it up. She has failed to meet every single IEP or IFSP speech goal she ever had. She picks up new signs everyday, from us, from friends, from church, even from TV. We have never had to sit down and show her a picture and then sign "dog", like they do in her speech classes.
She uses her voice (mostly for jabbering and sound affects) and maybe someday she will speak, but that is not our focus. Our focus is the ability to communicate. She was able to request a cookie when she was 18 months (BEFORE we found her hearing loss) only because of ASL. We never lost the ability to teach her rules or for her to tell us that she didn't like the taste of potatoe soup BECAUSE of ASL. Maybe your child didn't have the gaps in communication but SO many orally educated children do. They go years without the ability to communicate at all and that is NOT ok. And that is the reason I advocate ASL for ALL children with a hearing loss.
Oh, and in our local TC classes, they use ASL signs in English word order while speaking English, not SEE. So I guess it depends where you are from...though our school just mereged our TC class with Bi-Bi so it doesn't even apply here anymore.
Also wanted to say, that I believe our local Deaf community is very open. I know Deaf adults with CI's, those who speak and sign at the same time, those who live voice-off. They welcome hearing parents and kids with CI's all the time. The only requirement to be welcomed in our community is show up! If you come, you will be welcomed and they will try to figure out how to talk to you...even if it is just the old fashioned paper and pencil. I know it is different in other areas, and for that I am sad. I just wanted to leave my .02 and say that I am thankful for the people who are around us.