What's in a name?

The analogy of the waterfall acts as a good visual for both the swallowing process and speech production. For adequate swallowing function, pressure needs to be applied to the food or liquid through lip closure, chewing and tongue movement. The back of the tongue retracts to transport food or liquid to the throat (pharynx). The pathway is not straight or smooth much like the pathway of a creek or river leading up to a waterfall There are bumps and crevices, then over the back of the tongue (tongue base) the material flows into more cavities until the esophagus is opened and the material is fully swallowed.

This analogy is basic, but effective.

The swallowing process is intricate with neurological, anatomical and physiological safeguards to prevent material from flowing into the wrong tube (airway) or flowing in the wrong direction.

Flow can be visualized in a different way for speech. Producing speech is a completely human process. It requires coordination of respiration/breathing, airflow to vibrate vocal folds/cords to produce sound, movement of the articulators (lips, teeth, tongue) to change the sound into speech sounds. Words need to be made out of speech sounds to convey meaning in the shared language of both the speaker and the listener. Tone/pitch/emphasis is used and changed to match the appropriateness of the audience, location, and background noise.

Speech production can be visualized as a waterfall flowing out of the mouth, starting at the support given by the lungs then up through the voice box through the vocal cords, up over the tongue base and out of the mouth.