I am working as a test engineer. I have 3 years of experience in software testing. But I always have trouble expressing my ideas. I work very well but others are taking advantage of my work.
I think your communication skill will be improved over time, you can, of course, speed-up this by reading books (especially relevant to your field).
As your field is also in software testing, you will find out that sometimes some standard implementations of solutions is also a language of communication. An example is the Design Patterns reading a books about design patterns will help you improve your communication skills but also to understand some standard solutions to problem which will then you can use to communicate with your team. Example if the software makes use of the Singleton Pattern, if both in the conversation knows about this pattern, you don't have to analyse how it works, while is a standard solution, referencing to the name of that pattern is enough to understand each other.