Short answers, pulled from the story.
The earliest attempts to write the Egyptian language using Greek letters date back to the Ptolemaic Kingdom. Efforts to write Coptic in the Greek alphabet probably began in the first century BC.
Bohairic, the dialect of Lower Egypt, gained prominence in the ninth century and is now the dialect used by the Coptic Church liturgically. Modern revitalisation efforts are based on the Bohairic dialect which serves as the liturgical language of the modern Coptic Orthodox Church.
Fatimid Caliph Al-Hakim bi-Amr Allah issued strict orders completely prohibiting the use of Coptic anywhere whether in schools public streets or family homes. Those who did not comply were liable to have their tongues removed to intimidate others against speaking Coptic.
Six major dialects define the landscape of the Coptic language including Sahidic, Subakhmimic, Bohairic, Akhmimic, Fayyumic, Lycopolitan, and Oxyrhynchite. Sahidic remains the only dialect with a considerable body of original literature and non-literary texts.
The last known literary work written in Coptic dates to the late fourteenth century. As a primary spoken language Coptic was the majority language until between the tenth and twelfth centuries and survived as a minority primary language until at least the seventeenth century.