5. Arabic — 315 Million Native Speakers
Recent numbers put Arabic at around 315 million native speakers. But this is another instance of numbers not telling the full tale: Arabic, like Chinese, is so vastly different in its respective dialects as to be effectively a number of languages, grouped as one for the sake of convenience. Modern Standard Arabic is a primarily written form, closely related to the Classical Arabic of the Quran. However, the spoken forms of Arabic in, say, Oman and Morocco are so different that a couple of philosophy professors from these countries might be able to discuss the finer points of the ancient texts while still struggling to order lunch.
