Huruf-huruf Arab, sebagaimana yang kita kenal sekarang, tersusun dari garis dan titik. Titik-titik tersebut disebut i'jam. Tulisan Arab kuno tidak memilikinya, melainkan hanya terdiri dari goresan saja.

The Arabic letters, as we know them today, are made up of lines and points. The latter are called i'jam. The ancient Arabic script did not have them, but consisted of strokes only.

Penambahan titik-titik diakritik pada tulisan kerangka huruf membantu membedakan berbagai huruf yang mudah tertukar.

The addition of diacritical points to the plain writing of strokes helped to distinguish the various letters which could be easily mixed up.

Contoh: XXX XXX Tanpa titik, kata ini tidak dapat dengan mudah dikenali. Dengan i'jam, huruf-huruf dalam kata ini dapat dengan mudah dibedakan.

Example: XXX XXX Without dots this word cannot be easily recognized. With i'jam, the letters of this word can easily be distinguished.

Meskipun i'jam (titik pembeda huruf) sudah dikenal pada masa pra-Islam, penggunaannya jarang. Salinan-salinan mushaf Al-Qur'an yang sangat awal (dan tulisan Arab pada umumnya) tidak memiliki tanda-tanda ini. Tanda-tanda tersebut diperkenalkan ke dalam tulisan Al-Qur'an pada masa khalifah Umayyah kelima, 'Abd al-Malik bin Marwan (66-86H/685-705), dan pada masa pemerintahan Al-Hajjaj di Irak, ketika semakin banyak kaum Muslimin mulai membaca dan mempelajari Al-Qur'an, sebagian di antara mereka tidak banyak mengetahui Al-Qur'an, sementara yang lain berasal dari non-Arab. Dikatakan bahwa tabi'in terkenal Al-Du'all adalah orang pertama yang memasukkan titik-titik ini ke dalam teks Al-Qur'an.

Although the i'jam (diacritical points) were already known in pre-Islamic times, they were rarely used. The very early copies of the Qur'anic manuscripts (and Arabic writing in general) did not have these signs. They were apparently introduced into the Qur'anic script during the time of the fifth Umayyad Caliph, 'Abd al-Malik bin Marwan (66-86H/685- 705) and the governorship of Al-Hajjaj in Iraq, when more and more Muslims began to read and study the Qur'an, some of whom did not know much of the Qur'an, and others were of non-Arab origin. It is said of the well-known tabi'l Al-Du'all that he was the first to introduce these points into the Qur'anic text.