All the human beings - not only the Arabs - are addressed by the Holy Quran.
Montgomery Watt (2006 - 1909) confirms in his late book Islam and Christianity in the Contemporary World:
"The Qur'an is not in any way the words of Muhammad, nor is it the product of his thinking, but is the word of God alone, which is intended to address Muhammad, his contemporaries and whoever comes after them." Hence, Muhammad is no more than a "Messenger" chosen by God to carry this message to the people of Mecca first, Then all the Arabs, and hence it is a clear Arabic Quran. There are indications in the Quran that it is directed to the whole human race. It has been practically confirmed that Islam is spreading in the whole world, and accepted by humans of almost all races "