Ibn Khallikan
The 10th-century biographers Ibn al-Nadim and Abu Bakr al-Zubaydi, and in the 13th-century Ibn Khallikan, attribute Sibawayh with contributions to the science of the Arabic language and linguistics that were unsurpassed by those of earlier and later times. He has been called the greatest of all Arabic linguists and one of the greatest linguists of all time in any language.