When a person is looking for a way to communicate in alternative ways, they need to find something that really works for them. They need to try to find a voice that sounds natural. They want to try to find a way to be efficient. They want to be able to communicate as normally as possible, even though they're not using their biological voice.
As your child with CP is becoming a teenager, there are a couple of things you may want to think about.
Many of our products today have accessibility supports in them to the extent where we don't have to purchase anything else. It's already in there. Your phone, your tablet, your smart home devices. If you're going to look for these features on your devices, you can start in your settings. There should be something in there that says accessibility. Go in there, see what's available. The manufacturers have done a really nice job of describing these features right within the settings to give you a sense of what they're going to do.
Weight, height and body composition are important indicators for development. The tools used to measure these can be different for children with cerebral palsy.