There are two main types of written Arabic:
Classical Arabic - the language of the Koran and classical literature. It differs from Modern Standard Arabic mainly in style and vocabulary, some of which is archaic. All Muslims are expected to recite the Koran in the original language, however many rely on translations in order to understand the text.
Modern Standard Arabic - the universal language of the Arabic-speaking world which is understood by all Arabic speakers.
Classical Arabic has 28 consonantal phonemes (including two semi-vowels), originally corresponding to the 28 letters of the Arabic alphabet. Arabic has six vowel phonemes (three short vowels and three long vowels); they appear as various allophones, depending on the preceding consonant. Note that Arabic is particularly rich in uvular, pharyngeal, and pharyngealized ("emphatic") sounds.
The Arabic noun can take one of three states of definiteness: definite, indefinite or construct state. The definite state is marked by the article al-. The indefinite state is marked by an ending -n. The construct state is unmarked and occurs in the first member of a genitive construction.
An Arabic noun can take three cases: nominative, genitive and accusative, and three numbers: singular, dual and plural. Normally, nouns take the ending -u(n) in the nominative, -i(n) in the genitive and -a(n) in the accusative. The case endings are only present in formal or literary language. Technically, every noun has such an ending, although at the end of a sentence, no inflection is pronounced, even in formal speech, because of the rules of 'pause'.
The plural of a noun is formed by a suffix in some cases (sound plurals), but frequently, the vowel structure of a word is changed to form the plural (broken plurals). The plurals of nouns representing humans usually use sound plurals. Masculine sound plurals take the forms "-ūn" in the nominative and "-īn" in the genitive and accusative. In the feminine, the ending is "-āt" and is limited in its declension to the nominative and genitive endings. For example, "-ātun" and "-ātin" are possible, but not "-ātan". This pattern can also be used with for plurals of non-human nouns.
Arabic has two genders, expressed by pronominal, verbal and adjectival agreement. The genders are usually referred to as masculine and feminine, but the situation is more complicated than that. The 'feminine' singular forms are also used to express 'singulatives', which are plurals of inanimate objects of both grammatical genders.
A pronominal paradigm consists of 12 forms: In singular and plural, the 2nd and 3rd persons differentiate gender, while the 1st person does not. In the dual, there is no 1st person, and only a single form for each 2nd and 3rd person.
Enclitic forms of the pronoun may be affixed to nouns (representing genitive case, i. e. possession) and to verbs (representing accusative, i. e. a direct object). Most of them are clearly related to the full personal pronouns. They are identical in form in both cases, except for the 1st person singular, which is -ī after nouns (genitive) and -nī after verbs (accusative).
In Arabic, a word is classified as either a noun, a verb, a pronoun or a preposition. Adverbials are expressed with nominal forms. Repetitive use of the same root in verb and noun in a sentence is considered good style, especially with derived forms of the same verb. Also considered good form is constructing a long sentence joined together with connectors which are like conjunctions which allow for many clauses to run on and on in the same sentence.
There are many types of sentences:
Arabic vowel diacritics and other symbols
Arabic numerals and numbers
The first set of number names are Modern Standard Arabic. The others are Moroccan Arabic.