a letter in arabic (dad) many says that it is emphatic D but many recite it zad and some says that it is dad neither zad but it has middle voice which is produce when the tongue the upper teeth . so what's its real pronounciation

Question
a letter in arabic (dad) many says that it is emphatic  D but many recite it zad and some says that it is dad neither zad but it has middle voice which is produce when the tongue the upper teeth . so what's its real pronounciation

Answer
The Arabic letter is articulated from: one or both sides of the tongue and what lies opposite form it from the inside of the molars The posterior two thirds of the side of the tongue is used for this letter.  This letter can be articulated from one side (right or left) of the tongue alone, or from both sides of the tongue simultaneously. 
The should not be compared to a D, as they are very different in articulation points and in sound.  The tip of the tongue is not used in a correct , so it does not sound like a "d: or a "z".