If your TV is playing video normally, but not producing any sound, there are a few simple steps to test.
Firstly, if your TV is connected to soundbar or sound system, disconnect it and try playing audio through your TVs inbuilt speakers.
If this has not rectified the issue, ensure that the TV has not been set to "Mute".
Try using an alternate source, for example, if you are playing digital TV, try using a DVD player.
Lastly, try using a pair of headphones, if your TV has a suitable connection point, to determine if there is an issue with the speakers.