Peninsular Arabic
Peninsular Arabic, or Southern Arabic, are the varieties of Arabic spoken throughout the Arabian Peninsula. This includes the countries of Saudi Arabia, Yemen, Oman, United Arab Emirates, Kuwait, Bahrain, Qatar, Southern Iraq and the tribal people of Jordan (the native Jordanians).
Arabic
Within the non-peninsula varieties, the largest difference is between the non-Egyptian North African dialects (especially Moroccan Arabic) and the others. Moroccan Arabic in particular is hardly comprehensible to Arabic speakers east of Libya (although the converse is not true, in part due to the popularity of Egyptian films and other media).