The Official Language of the Umayyad Courts in Damascus, Syria and Cordoba, Spain was Proper Arabic (Fus-ha). There were a large number of Mawali (non-Arab Moslems) in both Umayyad Caliphates, but their culture and languages were sidelined for Arabic.
Arabic
Abd al Mallik unify the empire by making Arabic the official language of government in all Muslim lands
Umayyad A+ Umayyad Umayyad Umayyad
The Arabic language spread across the upper Middle East and North Africa by way of the Islamic conquests and the Umayyad and Abbassid Caliphates.
The umayyad were overthrown by the Abbasid
The emirs were governors in the government who ruled strictly to stop any disagreement
the methods that the umayyads used to unify their empire was the common language and the coinage!
It helped the scattered states from revolting
It helped the scattered states from revolting
It helped the scattered states from revolting
Damascus was the capital of the Umayyad Dynasty.
It depends on what you mean by "defeated". The Umayyad armies experienced their first major loss in Poitiers, France in 732 C.E. The Umayyad Caliphate in Damascus was overthrown by the Abbassids in 750 C.E. The Umayyad Caliphate in Córdoba, Spain collapsed in 1038 C.E. with the death of Hisham III without any successors.
The language of the universities and the government will vary from region to region. This is called a national language.