I like the concept of the global speaking but I wonder would it be better if you could just speak to everyone in the area you are in? Maybe we can do this already and I didn't find it but for me it would make sense if I hit the "T" key I would talk in my area, the "G" key for a global message.
I just think of this because sometimes you need say a hard bubble or some other item and if you could get it from someone in the same area as you without cluttering the global chat that would be cool
If this already exists though you can get rid of the post ^_^