Why Sylhet division? There is no standardize Sylheti language spoken all over the division. It varies with region to region like any other part of Bangladesh. This is not only limited to Sylhet region. In my district(Tangail) there are variation on how people speak in northern part of the district and southern part. In Bangladesh, every 50 km, dialect change. Within Sylhet division, people of Sunamganj district(part of Sylhet division) do not speak in Sylheti dialect. Their dialect is more closer to Mymensingh. None of the famous literate from Sunamganj ever used Sylheti dialect in their literature, not Hason Raja, not Baul Samrat Shah Abdul Karim. I am sure there are also variation in Habiganj district. I have noticed Sylhet and Moulovi bazar have similar dialect which you claim to be a separate language. People from this two district constitute the bulk of the diaspora Sylheti. Whether Sylheti is a separate language or a dialect of Bengali is a non issue in Bangladesh. You are trying to create a fissure where there is none. I do not remember any prominent Sylheti from Bangladesh or even from diaspora ever agitated to recognize it as a separate language. It is only a topic for a fringe group of Sylheti in UK and USA who are extremely alienated from both their mother country and adopted country. You seems to be one of them.
As I am from the sunamganj area.
The bit in bold is true I think, as when I go to syhlet city I understand pure syhleti less.
Does that the pure syhleti bdesi American will put me a gas chamber?