Saheh Character and Mu'tal Character
in Arabic there are Saheh Character (الحروف الصحيحة) and Mu'tal Character (الحروف المعتلة) : click the picture to enlarge Mu'tal Character (الحروف المعتلة) are alef (ا); wawu (و) and Ya (ي) for example in this words: قالَ دعاَ وجد يقول يدعو يبس يبيع يشتري Sahih Characer (الحروف الصحيحة) is words without Mu'tal Character, for example: باب ابن عنب