Abu Ja'far Muhammad ibn Abi Sara Ali Al-Ru'asi (Arabic: أبو جعفر محمد بْن أَبِي سارة الرُّؤاسيّ; died 187AH/802CE) was an early convert from Judaism to Islam and a scholar of the Arabic language. He is considered to be the founder of the Kufan school of Arabic grammar,[1][2][3][4] as well as the first person to write about Arabic morphology and phonology.[5] He was a student of Abu 'Amr ibn al-'Ala' and an associate of Al-Khalil ibn Ahmad al-Farahidi.[4][6]
It has been suggested that Sibawayhi, the ethnically Persian father of Arabic grammar, borrowed heavily from the works of al-Ru'asi for the latter's infamous Kitab though there is no textual evidence to support this.[6] We do know of a linguistic exegesis of the Qur'an complete with a glossary which was penned by al-Ru'asi, but it is no longer extant.[7] Although he is regarded as the founder of the Kufan school, very few details are known about al-Ru'asi's life or his views on specific matters of dispute in Arabic grammar and he is rarely quoted by later grammarians.[8]