ʿAbd-Allāh ibn Abī Isḥāq al-Ḥaḍramī (Arabic, عبد الله بن أبي اسحاق الحضرمي), (died AD 735 / AH 117) an Arab grammarian and is the earliest known grammarian of the Arabic language. He compiled a prescriptive grammar by referring to the usage of the Bedouins, whose language was seen as especially pure (see also iʿrāb, aʿrāb).
Two students of Abi Ishaq's were ʿIsa ibn ʿUmar al-Thaqafi (died 149 H) and Abu ʿAmr ibn al-ʿAlā' (died 154 H.). Al-Thaqafi seems to have had more prescriptive views while al-Ala's were more descriptive. Their differences have been suggested to lie at the core of the late division of Arabic grammar into the schools of Kufa and Basra.