Teacher perspective of student oral fluency

In a typical English classroom in Hong Kong, students often have a lack of opportunities to speak. When they do, teachers expect too much of their students' oral performance. They want students to speak with a high level of accuracy and fluency. That's why when they comment on student performance, they tend to spend a great portion of time highlighting the mistakes students have made. It is no wonder that we often hear English teachers say something like, 

"I can make students speak and speak, but what is the point if their mistakes are not corrected? They will never improve."

While it is important to give constructive feedback, we should be reminded that students cannot possibly internalize everything teachers tell them because of their cognitive load. In order to be effective, teachers should select a limited number of target areas for commenting, depending on student capabilities, for example, pronunciation, tense and collocation. Equally important, we should focus on the parts that students do well and build up their confidence to speak. Otherwise, I can make students speak grammatically, but what is the point if they focus on avoiding mistakes but not genuine communication?