The term "Arabic" may refer to either literary Arabic ( (al-)fuṣḥā الفصحى) or the many localized varieties of Arabic commonly called "colloquial Arabic." Arabs consider literary Arabic as the standard language and tend to view everything else as mere dialects. Literary Arabic (اللغة العربية الفصحى translit:al-luġatu l-ʿarabiyyatu l-fuṣḥā "the most eloquent Arabic language"), refers both to the language of present-day media across North Africa and the Middle East and to the language of the Qur'an. (The expression media here includes most television and radio, and practically all written matter, including books, newspapers, magazines, documents of every kind, and reading primers for small children.) "Colloquial" or "dialectal" Arabic refers to the many national or regional varieties derived from Classical Arabic, spoken across North Africa and the Middle East, which constitute the everyday spoken language. These sometimes differ enough to be mutually incomprehensible. These dialects are typically unwritten, although a certain amount of literature (particularly plays and poetry) exists in many of them. They are often used to varying degrees in informal spoken media, such as soap operas and talk shows. Literary Arabic or classical Arabic is the official language of all Arab countries and is the only form of Arabic taught in schools at all stages.
The sociolinguistic situation of Arabic in modern times provides a prime example of the linguistic phenomenon of diglossia, which is the normal use of two separate varieties of the same language, usually in different social situations. In the case of Arabic, educated Arabs of any nationality can be assumed to speak both their local dialect and their school-taught literary Arabic. When speaking with someone from the same country, many speakers switch back and forth between the two varieties of the language (code switching), sometimes even within the same sentence. When educated Arabs of different nationalities engage in conversation (for example, a Moroccan or Saudi speaking with a Lebanese), both switch into Literary Arabic for the sake of communication.
Like other languages, literary Arabic continues to evolve. Classical Arabic (especially from the pre-Islamic to the Abbasid period, including Qur'anic Arabic) can be distinguished from Modern Standard Arabic (MSA) as used today. Classical Arabic is considered normative; modern authors attempt (with varying degrees of success) to follow the syntactic and grammatical norms laid down by Classical grammarians (such as Sibawayh), and to use the vocabulary defined in Classical dictionaries (such as the Lisān al-Arab.) However, many modern terms would have been mysterious to a Classical author, whether taken from other languages (for example, فيلم film ) or coined from existing lexical resources (for example, هاتف hātif "telephone" = "caller"). Structural influence from foreign languages or from the colloquial varieties has also affected Modern Standard Arabic. For example, MSA texts sometimes use the format "A, B, C, and D" when listing things, whereas Classical Arabic prefers "A and B and C and D," and subject-initial sentences may be more common in MSA than in Classical Arabic. For these reasons, Modern Standard Arabic is generally treated separately in non-Arab sources.