Teachers should leave lecturing technique to teach in the classroom. There are some reasons why they should do that.
1. Lecturing tend to make learners less active.
Lecturing requires learners to listen to teacher's utterances during the process of learning. They only listen and write what the teachers say. They don't do anything. Just waiting and eye contacting to teacher. In language teaching, applying this lecturing technique will not improve the students' ability. The learners don't have sufficient chance to practice their skills.
2. Lecturing is boring.
Lecturing is boring for some learners. Moreover, the teacher doesn't have good public speaking. In 5–10 minutes, Learners' concentration is high. But more than 10 minutes, the concentration will fall into lower level. We sometimes find someone sleep while the teacher gives lecture.
3. Lecturing ignores learners creativity.
Everybody has their own creativity. One another has their own way to solve problems. Lecturing ignores this creativity. Teacher gives lecture as like he/she knows everything. Teacher has his/her own theory to tell to the students. How will the learner learn something? They never have a chance to find something by their own view. They only wait and see what will happen.
4. Lecturing ignores the social factor.
Learners are human socialism. They should have chance to work with others as human. Lecturing never gives that way. Learners never collaborate to solve problems or find something to learn.
Those are 4 reasons why teachers should leave lecturing. Lecturing may be good for introducing something in the beginning of the lesson but not as the whole technique. Now, it's time to make your students more creative and more active in the learning process. It's not the time to teach anymore, but it's time to give them time to learn.