No sound when tapping a phrase

First check the device itself: turn the volume up with the hardware buttons and make sure the mute or silent switch is off — that is the cause more often than anything else. Then open Settings, Voice and Accessibility, and tap Test my voice. If you hear it there, sound is working and the phrase you tapped will speak too. Some browsers wait for a first tap on the page before they will play any sound; tap once anywhere and try again.