What is the author's style in Lonesome Dove by Larry McMurtry?

Written in English, Lonesome Dove includes many terms and expressions from the time, beginning almost right away with referring to getting a whore as "getting a poke", and continuing with expressions like "I God", used to begin a sentence of surprise. Dern is commonly used in place of darn, and the book is peppered with quaint expressions like "Well, I swear" as an exclamation, making the trip back in time more realistic. The Texas drawl is easy to imagine as one reads the beginning, and Larry McMurtry's grasp of the time period is wonderfully well rounded. There is a quest, an adventure, a romance, a setting of cowboys and Indians, and the brutality and raw unsettled country are aptly portrayed all at the same time.