Kurdish is also widely spoken in areas primarily comprised of ethnic Kurds, although many ethnic Kurds speak Turkish as a second language or are actually native Turkish speakers. Kurdish is a language related to the Iranian languages, including Farsi. While Turkish is the primary language of communication from ethnic group to ethnic group within Turkey, English is the most important second language in the country when dealing with foreigners and nearly everyone speaks at least a minimal amount of English. In cities like Istanbul many people are completely fluent in English and carpet salesmen throughout the country can speak enough of a dozen languages to sell a carpet, but may not have the linguistic skills to have a simple conversation about anything else.
Religion
Today there is no official religion in Turkey and there is a distinct separation of Mosque and State. Despite this, nearly every Turkish citizen is a Muslim, including both the Turks and the Kurds.
Islam (the name of the religion, whose followers are called Muslims) is a monotheistic religion, whose holy book is called the Qur'an. The Qur'an is believed to be the word of God spoken through the prophet Muhammad from 609-632 CE (Common Era is preferred over AD (Anno Domini or "year of the Lord") since the Islamic world doesn't believe Jesus was the messiah). Islam believes Muhammad was the last prophet sent to earth by God, the last in a long line of prophets, which includes Moses, Abraham, and Jesus among others.