You already use different varieties of English in different parts of your life;
This is something I noticed more prevalently when i got to college since there are so many people from so many different places. Even people from different parts of New Jersey have different phrases and accents and ways of speaking english.
Every time you communicate, you signal some aspect of your identity.
I completely agree with this statement. No matter what you are saying or if you are speaking at all, every single piece of communication you make is rooted in what you have learned and your past experiences.
idiolect
I had never heard of this word before, but I think it is interesting. Everyone has their own idiolect without even realizing it or knowing what the word means.
Reading language rhetorically means figuring out why and how it works or fails to work in achieving its communicative purpose.
thinking rhetorically is one of the most important things to do while you read so you can fully understand what is the reason for the writing. This will help you understand the true meaning and help you fully understand it.
critical? How does being a critical reader, writer, and thinker differ from being an ordinary reader, writer, and thinker?
I think being critical reader, writer, and thinker means not just taking information in or putting words on a page, but attempting to fully understand what you are reading, writing, or thinking and finding ways to apply it.