They may also practice choreography and work on their stage presence. Rehearsals can be grueling and repetitive, but they are essential to ensuring a successful performance. In technical terms, singing is a physical process in which air traverses through the larynx, throat, and mouth. The vocal resonation in singing involves seven parts of the human body: the chest, tracheal tree, larynx, pharynx, oral cavity, nasal cavity, and sinuses. Songs are thought to have been used even before the birth of modern languages, dating back to the oldest recordings of humankind (as early as 800 B.C.). Until the fourteenth century, singers in Western culture were frequently constrained to singing only in churches. The emergence of operas and subsequent performances paved the way for today’s professional singers.