Check out the list on the commands page.
A good quality microphone makes a huge difference. Don't use the microphone built into your computer- use a headset if at all possible. Also, keep the microphone away from your speakers, so it can't hear other xplane noises.
Speaking slowly and clearly helps you be understood, just like in real life.
If you don't see the headset icon move with your voice, you either have a lot of background noise or the plugin can't hear you at all. Check that your microphone is selected properly in the sound control panel.
Everyone is different, so it's hard to make a recommendation; you'll have to try it yourself. I highly recommend that you try the free version to make sure that everything works for you before buying. If you're having trouble, send me an email and I'll see if I can help: email@example.com
See the list here.
Many other aircraft will work properly; I just haven't tested them. If there's a plane that you would like to have supported, feel free to email me.
Instructions are on the download page.
X-Plane 11 is fully supported- this is the version I recommend using.
X-Plane 10.50+ isn't officially supported, but should work. I don't officially test with XP10, but have many users still using it. Due to limitations of the X-Plane plugin system, the plugin definitely will not work with any version before 10.20, and does not support X-Plane 9 in any way.
PlaneCommand gets updated regularly. Updates are free. You can always get the latest version on the download page.
The voices available to you depend on your operating system. You can select from several while inside X-Plane by going to Plugins->PlaneCommand->Select voice.
Need help with something else? Email me: firstname.lastname@example.org