How to pronounce “chark” in English

So if you take, for example, the cotton yarn that it takes to weave the denim for a pair of jeans, that's about 6 miles of cotton thread.And before the Industrial Revolution, Indian spinners using the charka, who were the best and fastest in the world at spinning cotton,would have taken about-- an Indian spinner would have taken about 100 hours to spend that much thread for that single pair of jeans