Why can humans speak, but not animals?

A lot of organs such as lungs, larynx, mouth, pharynx, tongue, teeth, and brain participate in the speaking process. Although animals possess all these organs, their structure is different from that in the humans. For speaking, it is important to properly control the processes involved, mainly breathing. This is done for us by our brain. First the air is inhaled, and then deviated through the larynx from the lungs. The larynx has small muscles called the vocal cords. When the air passes through the stretched elastic vocal folds it causes them to vibrate, producing sound. The teeth, tongue, gums, and lips then form the words.