Q. Why are the beginning and end of prayers aloud but the rest quietly?
A. The beginning and end of each prayer provides the basic structure which denotes that we are loyal to the principles of tradition. Within those principles, we each daven at our own speed and with our own needs. The Meshech Chochmah says that by davening quietly we do not embarrass people who are confessing their sins. It is better not to listen in to other people’s private prayers.