Arabic is a Central Semitic language and, including all varieties of the language, there are 310 million Arabic speakers. It is the official or co-official language of 25 countries such as Algeria, Palestine, Tunisia and the United Arab Emirates. In general, Arabic can be divided into two main versions: Modern Standard Arabic and Colloquial Arabic. Modern Standard Arabic is the direct descendant from Classical Arabic, the language of the Quran. It is mainly used for formal situations and serves as a lingua franca for speakers of different dialects. Colloquial Arabic is used in the daily spoken context and therefore includes numerous regional dialects, some of which are mutually unintelligible. All varieties of Arabic are written with the Arabic script, which is read and written from right to left. The alphabet contains 28 letters. The three long vowels are included in the written words, but the three short vowels are only indicated by dots above and below letters. Arabic shows the fullest development of typical Semitic word structure. The words are composed of two parts – the root, which provides the general meaning of the word and the pattern, which gives grammatical meaning to the word. Suffixes and Affixes act as subject markers, pronouns, prepositions and definite articles. There are three cases in the declensional system of Modern Standard Arabic, but in the modern dialects, nouns are no longer declined.