The authenticiy and historicity of Old Bohairic pronunciation is well established. What is lacking from most of the OB v. GB debate is the politics behind the scene.
When Dr Emile Maher Ishak reached his preliminary conclusions, his findings were not welcomed by many inside the Coptic church.
On 2[7] Hator 1685 AM (6 Dec 1968 CE) a meeting was held to discuss the Old Bohairic pronunciation
- Shaker Basilios (Head of Department of Coptic language, Institute of Coptic Studies, Egypt)
- Abba Gregorius (General Bishop for Higher Theological Studies, Coptic Culture and Scientific Research)
- Ragheb Moftah (Head of Music and Hymnology dept. Institute of Coptic Studies, Egypt)
- Head of Coptic Archaeology, Institute of Coptic Studies, Egypt
- Dr Kamal Farid Ishaq, teacher of Greek and Coptic language, Institute of Coptic Studies, Egypt
The committee decided that OB pronunciation is influenced by Sahidic, and 'corrupt', if I remember correctly. A few years later, Dr Emile Mahee Ishak earned his PhD from University of Oxford, UK.
It was ironic that the findings of Dr Emile Maher Ishak earned him a PhD from one of the top 10 universities world wide under the supervision of professors of linguistics, while the institute of Coptic studies, which is not even approved by the Supreme Council of Universities, Egypt, rejected his findings.
Instead of acknowledging his academic rigour as a researcher, the institute doubled down on its rejection without reading his thesis, as it was not available online for a long time.