The birthrate is high, and almost half the population is under fifteen years of age. Yemenis speak Arabic, which belongs to the Semitic language family.
Classical Arabic, the language of Islam and the Koran, is used on formal occasions.
The kingdom of Saba, with its capital, Marib, had existed since the first millennium is depicted in the Koran as a punishment from God.
The prosperity of the principal rival kingdoms, Saba, Hadhramaut, Awsan, Qataban, and Ma'in, was based on the cultivation and overland exportation of frankincense, myrrh, and spices to the Mediterranean.
Hinterlands towns include Shibam, Sayun, and Tarim in the Inner Wadi, and there are seaports at al-Mukalla and al-Shihr.
The approximate size of the nation, since some of its borders are not demarcated, is 187,000 square miles (North: 75,000 square miles; South: 112,000 square miles), or 482,100 square kilometers. The Tihama, a coastal plain and hilly area along the Red Sea, is fifteen to twenty-five miles (twenty-five to forty kilometers) wide.
The central mountains consist of wide plateaus and basins.