Ph.D. Programs supposedly take 4-5 years to complete. But on average, students in the humanities take 6-10 years to complete the Ph.D. (Goldsmith, Komlos and Gold 30).
In most cases, your first two years will be devoted to coursework, often combined with teaching assistantships (described in section IV below). At the end of the first year, many programs hold a "review" or give an exam to determine whether or not you will be allowed to continue in the program. If you are not continued, or you decide to drop out, you are granted a master's degree.
Your third year is usually spent preparing for and taking your "qualifying exams" (testing your knowledge of an area you've chosen to specialize in), and writing your dissertation prospectus (an outline of the research you plan to do in your dissertation). In your fourth year, you begin researching and drafting your dissertation under the supervision of an advisor you've chosen, and a committee assembled by you and your advisor. Your dissertation goes through several revision cycles in which you address comments from your advisor and committee members. Once you finish and they approve it, you earn your degree.
Ph.D. programs also require students to have a sound reading knowledge of at least one foreign language, tested by exam. The department often makes little provision for students whose language skills are weak upon entering the program. Paying attention to foreign language skills as an undergraduate can greatly facilitate meeting this requirement, which becomes millstone around the neck of many doctoral candidates.
You do not need a Master's degree to apply to a Ph.D. program. On the other hand, if you are not admitted to a Ph.D. program the first time you apply, or are not quite ready to commit to one, a Master's program can strengthen your skills and make you a better candidate for admission. Going this route will cost you time, however (at least a year).