What is a good way to word the warning ‘audio device not found’?

We have an application which needs an audio input device, or at the very least an audio output device to do anything useful with it. Our user base will include people with limited English ability, or for that matter reading ability. I've spent more time trying to find an answer (MSDN style guide, questions on this website, etc) than I think I should have determining if there is a simpler or better way of saying:

• No audio output device found.
• No audio input device found.
• no audio devices found.

I am thankful for any input.