According to our family lore, the name is German. Maxwell Hu, in his book about Tucker County, mentions that the Kalar folks are German. We think that the name was Koehler or Kahler or Kaylor. They may have been illiterate and spelled it as they heard it.
I have been in touch with a Kalar family living in northern Minnesota whose ancestor, John Kalar, immigrated to the US from Slovenia in the early 1900's. We found no connection between these folks and the Kalar folks of VA, MD, and WV.
They told me that, to their knowledge, the last name has always been spelled 'Kalar'.
I was in touch, via e-mail, with a gentleman who lives in Canada and has the last name of Kalar. He is from India!
There is a story in our family that Johnson Marshall Kalar gave considerable money for mission work in the area where the Kalar River is located - that the river and other places there were named for him. True? Don't know.
Are you part of this family? If so, I would like to hear back from you. My mother is a Kalar.