Arabic is a member of the Semitic language family. It is spoken in more than 20 countries around the world, and is the native language of over 150 million people. It is also an official language of the United Nations, the African Union and the Arab League. Modern Standard Arabic (MSA) is the official language throughout the Arab world. Dialects are spoken in most informal settings, such as at home, with friends, or while shopping.
Of all the spoken dialects, Egyptian Arabic is the most widely understood, due to Egypt's role as the major producer of movies and TV programs in the Arab world.  So if you study the Egyptian Arabic and you travel to any Arabic country, you will be understood and will be able to communicate with people.