Teeth have many purposes. Mainly, you use your teeth to chew food and speak properly. In addition to supporting proper chewing, teeth align with the lips and tongue to help form words by controlling the movement of air flow out of the mouth and are therefore necessary to maintain proper speech. Your teeth are important for digestion because digestion begins in the mouth with the teeth tearing, cutting, mashing, and grinding the food you eat. Teeth keep other teeth in alignment in the jaw and they also provide structural support for muscles in the face.