It is perhaps easiest to speak of the various ethnic groups in the country in terms of their first language.
Approximately half of the population speaks Persian and affiliated dialects as their primary language.
Rainfall varies from less than two inches (five centimeters) annually in Baluchistan, near the Pakistani border, to more than eighty inches (two hundred centimeters) in the subtropical Caspian region where temperatures rarely fall below freezing. Iran's population has not been accurately measured since the Islamic Revolution of 1979.
Recent population estimates range from sixty-one to sixty-five million.
Several important volcanoes, including Mount Damāvand, the nation's highest peak at approximately 19,000 feet, (5,800 meters) also ring the country.The arid interior plateau contains two remarkable deserts: the Dasht-e-Kavir (Kavīr Desert) and the Dasht-e-Lut (Lūt Desert).These two deserts dominate the eastern part of the country, and form part of an arid landscape extending into Central Asia and Pakistan.The rest of the population speaks languages drawn from Indo-European, Ural-Altaic (Turkic), or Semitic language families.The principal non-Persian Indo-European speakers include Kurds, Lurs, Baluchis, and Armenians, making up approximately 15 percent of the population.This also applies to many non-Iranians living in Afghanistan, Central Asia, northern India, and parts of Iraq and the Persian Gulf region. In English, "Persian" is the name for the primary language spoken in Iran.