I know that choosing a topic for your master's thesis may seem challenging and daunting at first. But maybe in retrospect you would consider this as one of the most enjoyable experiences you've ever had.
First of all, you have to choose a topic that is interesting to you , your supervisor and the research community. The reason for this is that you are going to spend so much time with this project. So, I believe that doing some thing you enjoy is critical.
Also, choose a topic that you have some expetise about. This is important. You do not need to pick up a topic that is completely new to you.
As you know, choosing a topic for your mater's degree is important for your career later on . You always have to pick up a topic that relate to your work. As a teacher, I suggest that you choose a topic that has to do with classroom. You want to do something special that opens up many doors for you in the future.
I gather that you are confused and did not even set your mind on one area e.g listening. It is time now to choose one area of these and then dig deep into it and read the literature. I think reading more will give you the chance to come up with different topics .At this point I suggest you go and discuss your topics and ideas with your supervisor . S/he will give you some advice and direct your to the right path.
Needless to say,narrow down your topic to something manageable . You do not want a very broad topic and not a limited one .
Well, I hope you find this useful. Good luck