The video, which was uploaded by the German research institution Max Planck Society, features the profile x-ray view of a man speaking, and it was captured in an effort to showcase a special new MRI technology that's able to image the movement in the body beneath the skin in real time. As he speaks (in German), you can see the distinct rhythmic movements of all kinds of muscles and tissues that are otherwise invisible to the naked eye when we verbally communicate. Specifically, you get a glimpse the lips, tongue, soft palate, and larynx flexing and shifting in all kinds of directions in order to form vowels and consonants.
It's a bit mesmerizing and also satisfying to realize just how much work is required in your mouth just to utter even the littlest statement, and to appreciate why learning to talk takes some time to figure out.
Also, who knew how freaking huge our tongues actually are?