Hi Xiaoyun,
The download for NUCLE is in tar bzip2 format.
You can open it from the command line in Linux or Mac using: tar -xvjf release3.3.tar.bz2
If you are using Windows, you can use a tool like 7-zip to extract it.
In NUCLE, the students were all undergraduates at the National University of Singapore. They generally had south-east asian first languages. See the
NUCLE paper for more information.
Hope that helps!
Chris