This is something that has always bugged me. I do not see these pairs of sentences as equivalent, but from the way several of my family and friends speak, they do. What do you think? Are they interchangeable, and if not, what do they each mean?
Everyone doesn't understand this.
Not everyone understands this.
We don't agree on many things.
We disagree on many things.
Hmmm well now that I write it out that way, the dis/don't agree sentences do look more interchangeable to me. Regardless, I'm curious what you all think.