Peace
Its a common misconception that only the Arabian peninsula (and west Mesopotamia) are racially Arabs, and the rest of the countries are Arabs only by language due to Islamic expansion. The reason the countries that are Arabs is because Multiple Arab tribes have migrated to those areas, due to the violent nature of life in the Arabian Desert, intermingled with the local population. For Example, the Maghreb (Libya, Algeria, Tunisia, and Morocco) were inhabited by Berber Tribes (non Arabs), and they remained that way even after the islamic conquests, however, at the ninth century, the Arabian Tribes of Hilal, Sulaym, Hassan, and many others, migrated to those areas, and intermingled with the local berber tribes. Because of this, most of the population of the Maghreb is considered Arab-Berber, because they can trace there origins back to those tribes. Arab tribes also left the Arabian peninsula before Islam, Banu Ghassan, left there ancestor home in Yemen and migrated into the Levant (Palestine/Israel, Syria, Lebanon), even before this, the nabateans (who spoke a language derived from Aramaic, which then shifted into Arabic), levant, and so was Palmyrene Empire, led by the famous Arab Queen Zenobia. Because of the influx of Arabian tribes these regions became Arab Land, remember the ones i mentioned above are not all of them, they are just the most prominent, also remember that this occurred BEFORE Islam. Sinai was also inhabited by Arabs before Islam (they were called the Arubu Tribes). Iraq did also, like Banu Lakhm, and the majority of Mesopotamia was settled with Arabs centuries before Islam, remember at least in Asia, most of what is today the arab world is actually Arab ethnically because of Arab settlement and not merely language, you cant just learn Arabic and call yourself and Arab, that would make many Islamic Scholars Arab, which they are not.
Some Arab look different from each other because they are not pure Arab, for example, my friedns great grandfather lived in the area known as Uzbekistan, he then migrated to mecca, married an Arab Women, and his sister married an Arab Man. There children are Arabs but they themselves are not Arab. And because they are not pure Arabs they look like Turkic people are still considered Arabs.
If your Northern Iraqi, then you could be Kurdish, Turkman, Assyrian, or even Arab. Or Even Mixed.
I am arab that traces his origin to Bani Tamim, my grandmother though was from Iran. She is an Iranian Arab (Iran is NOT an Arab Country, its made up of Lors, Kurds, Azeris, Tajiks, Persians, the majority, but there are Arabs who settled in the Khuzestan region, especially from Bani Kaab, my grandmothers tribe)
Here is a list of the Arabian Tribes:
http://en.wikipedia.org/wiki/Arab_tribesHere are the Arab tribes in Iraq:
http://en.wikipedia.org/wiki/Arab_tribes_in_IraqHope I helped
Peace