Linguistically, Farsi is only spoken in Iran as the official language and dialect.  The Language spoken in neighboring countries is mostly Dari which sounds quite different and sometimes odd and incomprehensible for Persian speakers. On the contrary, the fluent Farsi spoken in Iran is understood by the others. And remember Iran is the motherland. All the neighboring countries including Azerbaijan, Armenia, Georgia, Tajikistan, Uzbekistan, Afghanistan, Bahrain and even Bahrain have been part of Iranian territory just 2 centuries ago.