Two things are generally accepted as facts in in the EFL world : Teachers talk too much and students talk too little.
Pretty much everyone agrees that students learn to speak English by speaking English, especially by talking to other students at the same level. This doesn’t always happen though. If a teacher is talking too much then students don’t have the opportunity to talk.
Some teachers talk a lot because they see themselves as entertainers whose job it is to create a good vibe in the class. It can be easy to forget, though, that the purpose of the class is to create learning opportunities for students. While a good atmosphere is essential for creating the right basis for learning, it needs to be built on. When we check on our classes, one of the things we do is see how much time the teacher spends talking. If a teacher is talking too much, we make suggestions and give guidance as to how the teacher can cut down on talking. For example, we might ask the teacher to do more group and pair work ; ask more open questions ; use non-verbal cues instead of verbal cues for directing tasks ; ask for more verbal feedback from students.
At SwanELT we always try to balance the good vibe with genuine learning opportunities.