Generally speaking, Modern Standard Arabic (MSA) is a form of Arabic used to interact with books and official mediums of communication (legal documents, news, etc), most of which require an editor. MSA is not a language anyone grows up speaking, rather it is a language that is acquired through formal schooling. The more fluent and fluid one speaks or writes MSA, the more educated one presents themselves. However, when MSA is used in everyday contexts, it may not be understood and, in most regions, sounds like you are speaking Shakespearian English while ordering coffee at a cafe.
Arabic dialects are forms of Arabic spoken by Arabic speakers at home and in everyday scenarios. Dialects vary from one region to another with many sub-dialects also present. The further the dialect regions are from each other the more of a chance they have of not being fully understood. Generally speaking, Arabic dialects are traditionally not taught in school and required immersion among locals.
Since both MSA and Arabic dialects are living languages, and basic science tells us that everything that is living is in a state of constant change, so are these languages. Classical Arabic was in this state of constant change until its vocabulary became frozen to the medieval period. Classical Arabic is still used today (especially in sermons, to access older works, write classical poetry) and MSA is a modern form of the Classical written language. In the Arabic-speaking world, Classical and MSA are lumped together in one term known as fuṣḥā.
To be highly proficient in Arabic for everyday and professional settings, one is required to be fluent in a dialect and have various degrees of fluency in MSA and Classical Arabic. The field of Teaching Arabic as a Foriegn Language (TAFL) remains split between what Arabic should be taught and when. The integrated approach combining dialect and MSA is gaining popularity in the US and Europe. New to the field as well is the turn toward multilingualism. Interesting and exciting times lie ahead for the field.
So, what dialect should you learn? The answer lies in which population you wish to interact with the most. If it’s only to read books, then MSA and Classical. If it is people, know that Arabic speakers communicate across dialects through multilingual and cross dialect code-switching which may or may not incorporate MSA and non-Arabic languages. Arabic, as a living language, is also going through a process of mother tongue-based cross-spectrum communicative hybridization known as al-lahjah al-bayda’. Rarely, if any, is MSA alone used in these everyday contexts among Arabic-speakers as a whole. But the more MSA you know, on top of a dialect or dialects, reflects the more educated you are. Arabic speakers pepper their every day with MSA and Classical Arabic to sound formal and authoritative, similar to how American English speakers interpolate French or Latin phrases or terms.
