People that you don't normally talk to.
People in different departments.
People that have different lengths of employment (newbies and senior staff)
Okay, ask them the following questions:
Who are we?
What do we do?
What makes us better than the rest?
Who is our target audience?
What do they need?
If you get the same general answer from each employee then someone at your place is really paying attention to the brand. Congratulations. If you don't, and it's okay most of you won't, then it is crucial to schedule message training time immediately.
Employees are the front line of your business. It is crucial that their abilities go beyond answering the phone with a smile. They have to be walking brand messengers. Make sure that if they get caught in an elevator with your biggest prospective customer they will know exactly what to say.