Till now the researchers worked with English language plagiarism as the major mode of communication in the entire globe is English. Thats why the research publications are mostly published in English globally. Besides this, there are other reasons too.
If you are willing to start working for Urdu plagiarism, then it will be a good work as it will help the Urdu language users.
I wrote an article about the topic in question but it was about students trying to pass their final exams and purchasing ready-made papers.
By the way, it is not so difficult do unveil plagiarism, what is difficult is to make it public. A lot of externel factors would try to prevent you from doing it.