 TTT and STT, teacher talking time and student talking time. These terms are commonly used in English language teaching to refer to periods during a lesson where the class is either teacher-centered or student-centered, as well as the relative importance of each situation. Times during the lesson where the teacher is the only person talking, such as when presenting vocabulary or grammar structures, are often referred to as teacher talking time. In contrast, sections of the lesson where the students are the ones doing the talking, such as when practicing new language they have learned in the lesson, are often referred to as student talking time. The relative importance of these two situations is a source of some debate in English language teaching. However, modern methodologies often lean towards more STT, providing this time is spent in a productive manner.