Agile software development espouses frequent inspection, frequent adaptation, teamwork, accountability. All these would not really be possible if the team does not communicate.
Forming an agile team that is essentially weak in communication skills is a recipe for disaster.
In the first place, one of the main expectations of the team members are that they are fully functioning individuals. Individuals who are skilled enough to help work on the backlog. Individuals who are motivated enough to seek to understand what needs to be done or how to get things done. And of course, there is the daily updates wherein the team is expected to communicate their current progress, their plan for the day and whatever blocker they see that is stopping them from delivering. Without communicating, I do not see how this can be done.
For the longest time that I have been exposed and dealing with agile teams, communication skills (or the lack of it) continues to be an Achilles heel that really needs to be dipped again in the river Styx. It may be traceable to culture and how we are brought up. It may be a personality trait like shyness or lack of confidence. Or just plain ego.
Either way, communication skills are very important to getting agile to work.
Isn’t just speaking out what you are working on and having trouble with easier than dying hard trying?
my take 