The term 'Language in Tehran' can be summarized by the crossword solution of Farsi, which is the official language of Iran. Farsi is a Western Iranian language and is spoken by over 110 million people worldwide, primarily in Iran, Afghanistan, and Tajikistan. It is also known as Persian, and is written in the Arabic script. In Tehran, Farsi is the primary language used in everyday life, and is the language of instruction in schools.