Abu al-Aswad al-Du'ali

Abu al-Aswad al-Du'ali Zalam ibn Amr (died 69 AH / 688 CE) was one of the foundational figures of Arabic grammatical science and a leading scholar of Basra who is credited, along with Ali ibn Abi Talib, with laying the foundations of Arabic grammar as a formal discipline. He was from the tribe of Du'il and settled in Basra where he became an important religious and linguistic authority.

The traditional account holds that Ali ibn Abi Talib, concerned about the corruption of Arabic pronunciation and grammar that was occurring as the Islamic empire expanded and non-Arabs embraced the faith, gave Abu al-Aswad the first principles of Arabic grammatical analysis — the basic categories of noun, verb, and particle — and instructed him to develop the science. Whether or not this account is historically precise, Abu al-Aswad is universally credited as the first major systematizer of Arabic grammar.

He is also credited with introducing the system of diacritical marks (tashkil/harakat) to the Arabic script to indicate short vowels, using colored dots to distinguish different vowel sounds. This innovation was crucial for ensuring correct Quranic recitation as Arabic spread to peoples who did not grow up speaking it natively. The system was later refined by al-Khalil ibn Ahmad al-Farahidi into the form still used today.

He narrated hadith from Ali ibn Abi Talib and was known as a poet as well as a grammarian. He died in Basra during the plague of 69 AH. His contribution to the preservation of the Arabic language — and by extension to the correct transmission and understanding of the Quran — makes him one of the most consequential figures in the history of Islamic sciences.