What was the most common foreign language of countries central Asia in

It's difficult to definitively say which was the most common foreign language across all of Central Asia throughout history. It depends on what time period you're looking at and which countries are included in your definition of "Central Asia."

However, we can look at some key influences:

* Russian: For much of the 20th century, Russian was the official language of the Soviet republics that included Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan). Even after the collapse of the Soviet Union, Russian remains widely spoken and used in government, education, and business in many of these countries.

* Persian: Historically, Persian (or Farsi) has had a significant influence in Central Asia. It's the official language of neighboring Iran and has been a lingua franca in the region for centuries. Its impact is still felt today, especially in countries like Tajikistan and Uzbekistan.

* Turkic Languages: Central Asia is home to a diverse range of Turkic languages, including Uzbek, Kazakh, Turkmen, Kyrgyz, and others. These languages are all mutually intelligible to some degree and have served as common languages within certain regions.

Other Influences:

* Arabic: Due to Islamic influence, Arabic has also played a role in Central Asia.

* English: In recent decades, English has become increasingly important as a global language and is gaining traction in business, education, and technology.

Important Notes:

* Regional Variations: The most common foreign language in Central Asia varies depending on the specific country and region you are considering.

* Shifting Dynamics: Language use is constantly evolving. The dominance of Russian has been declining in some countries as other languages like English and Turkish gain prominence.

Ultimately, to give you a more precise answer, you would need to specify the time period and specific countries you are interested in.