Useful vocab: Marwanid Reforms, ‘Abd al-Malik, Arabization, diwan
NB: for continued use of Latin on post-Reform coins, see here.
A 7th- or 8th-century Inscription
This inscription is a mile marker to announce the distance to Damascus. It reads: “The slave of God, the commander of the faithful ‘Abd al-Malik – may God’s mercy be upon him – erected this stone. From here to Damascus is 109 miles”

An 8th-century Document
This contract on papyrus is dated 14 August 758 CE and records the sale of a building by Senuthius, son of Enoch, to Aaron, son of Senuthius. It was written in the town of Djeme in southern Egypt. It starts in Arabic, then switches to Greek, then to Coptic.

An 8th-century Document
This is a tax invoice from a monastery in Egypt, written in Arabic on top and Greek on bottom, dated to 709-10.

A 7th-9th-century Document
This is a personal letter written in the Latin script between the 7th and 9th centuries in Egypt. It starts out in Latin and then switches to Arabic (but keeps it in the Latin script). You can read about its contents here.

A 9th-century Description
This passage is from Baladhuri, a 9th-century Muslim who wrote a conquest narrative in Arabic.
Greek remained the language of the state registers [diwan] until the reign of ‘Abd al-Malik ibn Marwan, who in the year 81 ordered it changed. The reason was that a Greek clerk desiring to write something and finding no ink urinated in the inkstand. Hearing this, ‘Abd al-Malik punished the man and gave orders to Sulaiman ibn Sa’d to change the language of the registers. Sulaiman requested ‘Abd al-Malik to give him as subsidy the kharaj [taxes] of the Jordan province for one year. ‘Abd al-Malik granted his request and assigned him to the governorship of Jordan. No sooner had the year ended, then the change of the language was finished and Sulaiman brought the registers to ‘Abd al-Malik. The latter called Sarjun [Sergius] and presented to him the new plan. Sarjun was greatly chagrined and left ‘Abd al-Malik sorrowful. Meeting certain Greek clerks, he said to them, “Seek your livelihood in any other profession than this, for God has cut it off from you.”
Source, p. 301.