Can we talk underwater?How did harry styles sing "Falling" underwater?

I saw harry styles falling song and wondered how did harry styles sung underneath water...and here are the results!!!

If you ever tried talking to your friends underwater you might have discovered that it didn't work well....

As long as your breathing out to talk, not a whole lot other than maybe your mouth filling with a bit of water if the pressure your putting out threw your lungs drops, and creating a few bubbles. Now if you stop talking with your mouth open under water, your mouth could fill with water, and if your not careful and the air pocket in your throat and lungs gets disrupted, and you could take water into your lungs. Not good. And if you are foolish enough to try to take a “breath in” underwater, in order to talk, chances are you could drown.

So it really depends on what your doing while trying to talk underwater. I have done it before, though there's not much point. No ones likely to hear your voice threw the water and bubbles.

The short answer is still no, unless at a shallow depth.

Imaging going underwater with something that keeps your head surrounded by air, say a Kirby Morgan dive hat. Air is being supplied to you at a pressure greater than ambient, which increases with depth. As you go deeper and there is more pressure, the air you are breathing is denser. Much denser than the air you normally breathe, and that which vibrates your vocal chords. Now this doesn't effect the ability to speak but rather raises the tone of your voice. This can be noticed as shallow as 10 feet deep and gets more pronounced with greater depths to the point the you will start to sound like Donald duck, or even higher.

So no, you cannot talk normally underwater but yes talking is possible

Sources : Quora