I was talking with some native English speaker. She said something and I replied:
I don't understand.
Then she replied:
You no understand?
What does that line mean? I'm not sure whether there was a question mark at the end or not. I guess it means:
Don't you understand?
Edit
I don't think she knew that I am non-native English speaker. There were a lot of people chatting and I threw my first message, "I don't understand" and then she replied, "You no understand". Perhaps there was something on that website via which she could know that I was chatting from a non-English country. I don't think she was trying to mock me. There must have been some other reason.
Best Answer
"You no understand?" is not something a native English speaker would ever normally say.
The only situation where a native speaker would say this, would be when speaking to a non-native speaker. I can think of three reasons there: