This movie is from the website of the Speech Production and Knowledge Group (SPAN) at the University of Southern California.
It shows the vocal tract of a young lady, imaged with magnetic resonance technology, while she talks about her love of music. You can clearly see the tongue, lips and jaw moving, as well as the soft palate rising and falling, which dynamically changes the resonant properties of the vocal tract, imposing a "time-varying formant structure" onto the speech signal.