"Iran's Azeri Turks
If you hear a language other than Farsi on the streets of Tehran, most likely it's Azeri Turkish. Closely related but not identical to the national language spoken in Turkey, Azeri is spoken as a first language by about 20% of the Iranian population, mainly concentrated in the provinces of Eastern and Western Azerbaijan but it is also very commonly spoken in the capital. Estimates of just how many Iranians are ethnically Azeri Turks vary widely. One very commonly quoted statistic makes Azeris the largest single population group in Iran, making up 30 million of the country's population of ?70 million?."
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