Read the following excerpt from a biography on Mark Twain and answer the question. Samuel Langhorn Clemens, Mark Twain, was born in Florida, Missouri on November 30,1835. The experience of his life prepared him as a writer, an American writer. He worked as a printer, then apprenticed himself as a river pilot on the Mississippi, and eventually became one of the best. He worked at mining activities in Nevada. In 1862, he took a position on the Virginia City Enterprise where he first used the name Mark Twain, which was a riverboat pilot expression.

He went to the West Coast and worked for a while on the San Francisco newspaper, Morning Call. After leaving there, he went to Calaveras County to try his hand at mining. In 1865, he was asked by Artemus Ward to write a humorous sketch. He signed it "Mark Twain," and his reputation began on the eastern seaboard. In 1866, he was sent by the Sacramento Union to Hawaii. Unexpectedly, in 1867, he sailed abroad and wrote letters that were to become the book, The Innocents Abroad. With that book he became the most famous humorist of his time. In July, 1869, The Innocents Abroad was published. On February 2,1870, he married Olivia Langdon.

What is the best way to describe the language used in this excerpt?

informal language
formal language
critical language
objective language