A glance at how the Persian language emerged shows that Old Persian gradually evolved into Middle Persian by shedding its nominal inflection and simplifying its verbal system as well as discarding grammatical gender distinction and the dual. More than four hundred years of Sassanid rule with its centralizing tendency strengthened the case of this language and spread it beyond its original home, Persis or Fars in southern Iran, overwhelming some of the local languages and replacing them.
Persian served as the imperial language in India for 300 years, from the time of the Moghul Empire through the early British Empire. During the late 18th and early 19th centuries in both India and England, Persian teaching became highly contested by rival representatives of these conflicting imperial cultures.
The written Persian language is remarkable for its stability over a millennium of time. In contrast, the interesting thing about Ottoman written culture is that although Ottoman Turkish was intimately linked with Persian throughout its existence, although Ottoman scribes based their organization and culture on that of Persian scribes, and although Persian literature and documents formed the most important models for those of the Ottomans, the Ottoman written language was not at all stable or unchanging. To an Ottomanist, it seems odd even to think about an unchanging language, because Ottoman Turkish was constantly changing and the changes were one of its most notable features.
Of all the Iranian languages of Persia, current or defunct, Persian is the only language with a clear pedigree. We know its parent and its grandparent. We can even reconstruct its great-grandparent, old Iranian. Other languages are known either in their modern forms, such as Pashto, Kurdish, Baluchi, Lori, Tati, Mazandarani, Gilaki, and the Pamir dialects, or we know only their middle stage through written documents, partly excavated in archeological explorations, as is the case with Parthian, Sogdian, Bactrian, and Khotanese.
The deputy minister of science, research and technology for international affairs said: "About 90,000 foreign students are studying in Iranian universities, who have an effective role in promoting Persian language and literature."