Here in Kuwait the locals are a mixed variety of people. Most of the "original" Kuwaitis came from Saudi Arabia, particularly the "Nejd" area, but since the Arabian lands were open to all, the nomadic life led people whose origins were from all around to the little land of Al-Kut (which later became known as Al-Kuwait, meaning the little cottage.
The people who are Kuwaiti citizens today are basically from three places, Saudi Arabia, Iraq, and Iran. Naturally, there are Kuwaiti citizens from several other places due to naturalization based on several citizenship laws, and marriage (for naturalized women) but the people that benefited from such laws are few and far between.
The people from the three areas that are where the majority of Kuwaitis are from have cultural habits that differ somewhat from each other. Their foods are also somewhat different, although many of the Kuwaiti dietary habits have melded into the melting pot of Kuwait over the years since Kuwait has become an entity.