Book excerpt: Though there is a contingent of linguists who fight the fact, our language is always changing -- not only through slang, but sound, syntax, and words' meanings as well. Debunking the myth of "pure" standard English, tackling controversial positions, and eschewing politically correct arguments, linguist John McWhorter considers speech patterns and regional accents to demonstrate just how the changes do occur. Wielding reason and humor, McWhorter ultimately explains why we must embrace these changes, ultimately revealing our American English in all its variety, expressiveness, and power.