There's no sound in the navigation. Why?

Navigation without sound: 1, speaker short circuit; 2, sound file problem, may be installed incorrectly; 3. The voice switch is not turned on; 4. Navigation system without language navigation; 5. The sound hardware is not driven. General car navigation functions include DVD playing, radio receiving, Bluetooth hands-free, touch screen, optional function, intelligent track reversing, tire pressure detection function, virtual six-disc, background control function and so on. Vehicle navigation has the function of GPS global positioning system. As long as the driver inputs the destination into the vehicle navigation system, the system will automatically calculate a more suitable route according to the electronic map, and remind the driver to follow the appropriate route when the vehicle encounters turning and congestion.