Nexus 4 speaker no longer playing any audio The speaker on my Nexus 4 suddenly stopped playing audio a few days ago. No sound at all, no music, ringtones, etc.

Is this software problem or hardware?

If I reinstall Android 4.3 again manually, will it unmute the speaker?
First thing to do is to check the device's settings. It might very well be you just "silenced" your phone one way or the others. There are different places to look for:


Open the notification area. On many (recent) devices, it holds some shortcuts to frequently used stuff as toggling WiFi, airplane mode, and also mute (i.e. switch between "complete mute", "vibration only", and "normal noise").
Check all your stuff in the Settings menu. Different manufacturers/devices/ROMs have different settings in different places which might cause this
If you use some "automation tool" like Tasker, Llama, or the like, check whether it could be one of its profiles


If the above still didn't solve the issue, make a good backup and then factory-reset your device. If the device still stays mute after that, it's unlikely to be resolved on a software level, but rather a hardware failure. So in that case, you should contact the service; if the device is still under warranty, they should fix it for free.