This is a good question. If you do not want to communicate through words or body language, there are other options. Also in some ways symbols are more powerful than words. For example, a red flashing light is sometimes more powerful than words. With that said, let me offer two ways in which companies can communicate without words or body language.
First, as suggested above, visual signs can be a powerful way to communicate. Even our government uses this. In traffic, red signals stop, yellow communicates slows down, and green is for go. Also in emergency situations, red connotes the highest level of alertness. So, in view of this, companies can use visual signs to communicate to their employees.
Second, sounds can also be powerful. The sound of an alarm is pretty evocative of danger, for example. In like manner, a company may want to use sounds to alert people.