[Lessismore]

Arabic is a language and Arab designates the nation of those who speak it.

Since Arabic has been a language of empire and religion, it isn't really true that those who speak Arabic are all Arabs much more than those who speak English are all Englishmen.

[JasonC]

Fair enough, in the sense that it is also a sort of Latin throughout the Muslim world. But the political phenomenon of Arab nationalism is based on a desire for political unity of action among those whose native language is Arabic. For instance, one manifestation of Arab nationalism was the revolt against the Turkish Ottoman Empire during WW I. The fact that Arabic was the language of the Turk's religion did not make the Arabs feel great affinity with them. Instead it reminded them that the Turks were later-comers to empire, former mercenaries who had usurped and replaced the Arab rulers who hired them. Another example is gulf Arab support for Iraq in the Iran-Iraq war of the 1980s, which was definitely part based on Arab nationalist solidarity against Persian speakers, regarded as outsiders.