Arabic, a pure cursive script, is written from right to left and in which most letters must join with their neighbouring letters (both hand-written or printed) to make a word in accordance with some rules. It has no upper/lower cases (capital) instead each letter may have up to four recognizable shapes depending upon the combinations used; nevertheless, the distinctive shape of each letter can still be easily recognized.
Arabic writing system is widely used by several other African and Asian languages such as Urdu, Farsi,Sindhi etc.
Nearly every-Arabic letter can be joined to its neighboring from both sides (normal letters), and they can have up to four contextual shapes: (1) Isolated or Independent (2) Initial (3) Medial (4) Final. There are six letters known as partially-connecting letters ر ز و ا د ذ that have no initial and medial shape. Therefore, they can only be written as independent or at most be joined to its previous letter only (not on both side). For more information, please refer to Screen 00x
As a general rule, an Arabic word having two or more letters continuously joins to its neighboring letters (even in printed form) until such a word confronts partial connecting letters or final letter, in such case, continuous joining of letters is interrupted and subsequent letters, if any, will be written as separate joints (cluster).
A word may have more than one cluster. A cluster is set off first as Isolated or initial shape and then one or more medial shapes and lastly the final shape. Since late 1990, the most writing software and the web browsers now have built-in algorithm to join the Arabic letters. In a normal situation a cluster of Arabic letters always written close together. For the benefit of the novice, in the next few practice exercises the words will be shown with a slight gap between each letter, so that the different shapes, as well as the joining rules may easily be recognized. With some help from tables provided.