Dominant students in speaking activities
So you want to have a speaking activity, maybe a debate or at least something where students express their opinions and disagree with others in the class. You also have one or more students who like the sound of their voice too much, and others for whom "Good Morning" is a major undertaking in itself, not because of language ability but just because they are quite happy to let the dominant ones do the talking.
Instead of interrupting all the time when the students are debating, and trying to shut some people up and let others speak, you should hand out five pieces of paper, bits of Lego, rods, etc. These are their speaking tools. They cannot speak without them and when they do speak they must give one of them up to you. This is explained to the students at the beginning of the discussion, and then, every time a student wants to express an opinion they must give up one of their five pieces of paper etc. Students will soon realise that to interrupt another student with simply, "I am not agree!" and to say nothing more, is a big waste of their valuable speaking resources. They must therefore use their resources wisely, and make up a (hopefully) cogent argument with their time. Once a dominant student has used up their rods, you can either,
if you are strict, say "tough" and the student must keep quiet, or give a time limit and re-issue resources every five minutes. You'll soon find that the quieter students come out of their shells more once they have nothing to fear from the silent dominants.
Angus Savory 18-08-2011