Farsi

Farsi refers specifically to the modern Persian language as it is spoken and written in Iran. While the term Persian is often used as a broader umbrella for the language across different regions and historical periods, Farsi is the endonym used by native speakers in Iran to distinguish their specific linguistic identity.

As a proper noun denoting a specific language, it functions as an uncountable noun. It does not take a plural form and cannot be quantified with numbers, requiring a partitive construction such as a dialect of Farsi if one needs to discuss specific variations.