What is the author's style in The Fighting Ground by Avi (Avi Wortis)?

Since the story takes place in 1778, in the midst of the American Revolutionary War, there are some words used in the story that is indicative of that era. For example, the soldiers have "muskets," weapons that would now be called rifles. The soldiers have to string a gunpowder keg around their necks—their source of firepower when they are loading their "lead balls" which would in current days be called bullets. The houses are described as one-room buildings with "dirt floors." There are other examples. A young boy that Jonathan encounters is described as wearing a "linsey-woolsey" blouse. When the hungry Jonathan reunites with his soldiers, he is offered a "johnnycake." When the tavern keeper realized that Jonathan had lied about having his father's permission to join the fight, he called him "sly boots."