As for the question that which of them is older, then Persian takes the prize if we include the history of its earliest version. The Old Persian had been around since 550-330 BC until it transitioned into the Middle version of the tongue in 224 CE. Old Arabic, on the other hand, emerged in the 1st century CE.
The answer to this question is that the two languages are not directly related but have influenced each other. Persian and Arabic languages are two completely separate families and their origin is different.
The history of the Persian language is divided into three eras: Old Persian (ca. 525 BC- 300 BC), Middle Persian (c. 300 BC- 800 AD), and Modern Persian (800 AD to the present day).
Arabic and Persian are totally different languages, but both with a mostly common alphabet, overlapping vocabulary (nearly all going from Arabic to Persian), and with ties to Islam. The similarity is a bit like that between English and French.
7. Farsi – 522 BC (circa. 2500 years old) While not the earliest known language in the Indo-Iranian language family, Farsi is the longest surviving spoken language of the Iranian family of languages. It takes its roots from Old Persian, which was first attested somewhere between 522 and 486 BCE.
Greek is the third oldest language in the world. Latin was the official language of the ancient Roman Empire and ancient Roman religion. It is currently the official language of the Roman Catholic Church and the official language of the Vatican City. Like Sanskrit, it is a classical language.
Persian scripts have evolved over the last 3000 years, with three major historic stages of development, all on display in this exhibition. In ancient Persia (650 BCE–330 BCE), Old Persian was inscribed in the cuneiform script, adapted from the Mesopotamian cultures of the ancient Near East.
Over 1 million Iranian Sayyids are of Arab descent but most are Persianized, mixed and consider themselves Persian and Iranian today. The majority of Sayyids migrated to Iran from Arab lands predominantly in the 15th to 17th centuries during the Safavid era.
Iran and Turkey are not Arab countries and their primary languages are Farsi and Turkish respectively. Arab countries have a rich diversity of ethnic, linguistic, and religious communities. These include Kurds, Armenians, Berbers and others.
Linguistic affiliation
Persian is a subgroup of West Iranian languages that include the closely related Persian languages of Dari and Tajik; the less closely related languages of Luri, Bakhtiari, and Kumzari; and the dialects of Fars Province.
The ancient Persians were originally an ancient Iranian people who had migrated to the region of Persis (corresponding to the modern-day Iranian province of Fars) by the 9th century BCE.
Sumerian can be considered the first language in the world, according to Mondly. The oldest proof of written Sumerian was found on the Kish tablet in today's Iraq, dating back to approximately 3500 BC.
Persian, predominant ethnic group of Iran (formerly known as Persia). Although of diverse ancestry, the Persian people are united by their language, Persian (Farsi), which belongs to the Indo-Iranian group of the Indo-European language family.
The Persian alphabet is directly derived and developed from the Arabic alphabet. The Arabic Alphabet was introduced to the Persian-speaking world after the Muslim conquest of Persia and the fall of the Sasanian Empire in the 7th century.
In 642, Umar ibn al-Khattab, then-Caliph of the Muslims, ordered a full-scale invasion of Persia by the Rashidun army, which led to the complete conquest of the Sasanian Empire by 651.
Arabic is descended from a language known in the literature as Proto-Semitic. This relationship places Arabic firmly in the Afro-Asiatic group of world languages.
According to tradition, Arabs are descended from a southern Arabian ancestor, Qaḥṭān, forebear of the “pure” or “genuine” Arabs (known as al-ʿArab al-ʿĀribah), and a northern Arabian ancestor, ʿAdnān, forebear of the “Arabicized” Arabs (al-ʿArab al-Mustaʿribah).
The term Aryan has long been used to denote the Indo-Iranians, because Arya is indeed the self-designation of the ancient speakers of the Indo-Iranian languages, specifically the Iranian and the Indo-Aryan peoples, collectively known as the Indo-Iranians.
The vast majority of Iranians are Muslims of the Ithnā ʿAsharī, or Twelver, Shiʿi branch, which is the official state religion. The Kurds and Turkmen are predominantly Sunni Muslims, but Iran's Arabs are both Sunni and Shiʿi. Small communities of Christians, Jews, and Zoroastrians are also found throughout the country.
The Iranian peoples stem from early Proto-Iranians, themselves a branch of the Indo-Iranians, who are believed to have originated in either Central Asia or Afghanistan circa 1800 BCE. The Proto-Iranians are traced to the Bactria-Margiana Archaeological Complex, a Bronze Age culture of Central Asia.
The Y-chromosome analysis results suggest that Middle Easterners harbour a gene pool with greater affinity to African fathers. The mtDNA of the Middle Eastern population, however, did not show affinity to Africa. This suggests that when males migrated into North Africa, they left their female companions behind.
The Persians, Kurds, and speakers of other Indo-European languages in Iran are descendants of the Aryan tribes that began migrating from Central Asia into what is now Iran in the 2nd millennium bce.
Farsi is one of the oldest languages spoken on earth today, but that doesn't mean people can't understand it. In fact, Farsi speakers today are able to read and understand the Persian language of 1700 years ago with more ease than an English speaker might have reading an English text of even 500 years ago.
Parthian Empire (248 BC–224 AD)