This chapter book based on PBS's popular TV show Martha Speaks features two back-to-school stories, plus a glossary and activities. In the first story, T. D. adds Martha's name to the substitute teacher list at Wagstaff Elementary, but not even he expects a talking dog to actually fill in for Mrs. Clusky. Never one to ignore the call of duty, Martha takes the class under her wing—er, paw—but Helen's not sure their friendship can survive Martha's strict teaching style. In the second story, Alice is in agua caliente when she is assigned an oral report in Spanish class. She can't speak a word. But with the help of some Mexican alphabet soup made by Tio Jorge, Martha can! Is it cheating if a Spanish-speaking dog helps you with your homework?