praveenp wrote:
There is atleast one successful captcha php script for Malayalam Language (http://sourceforge.net/projects/mlcaptcha/ , http://mlcaptcha.blogspot.com/2010/02/blog-post_24.html ). I don't know whether it can work with mediawiki.
It could be added, although I find that particular captcha easier for bots than for humans. And an attacker can easily play with the parameters to weaken it even more.