If you talk and eat at the same time, you run the risk of choking and coughing violently, and blocking your airway with food. We often describe this situation by saying the "food went down the wrong way." What is the biological explanation for the situation that this phrase describes?

It means that food particles have entered the trachea. The epiglottis is an organ that prevents food entering the trachea from esophagus. Chewing and talking can result in the epiglottis, which is located in the larynx (voice box), to move in awkwardly during swallowing rather than flatten and cover the windpipe.