Farsi is the main language of Iran. Many English speakers also call it Persian, and that is not a different language — it is the older English name. Farsi is what the language calls itself. Though actually, people argue about the English word: some Iranians like Farsi, while some teachers prefer Persian because it also covers close kinds of the language spoken in Afghanistan and Tajikistan. For a learner, both names point to the same thing: Iran’s language. English only started using Farsi widely in the late 1960s or early 1970s. Iran’s everyday language is not Arabic, even though the writing system is related and Arabic is used in religion.