Currently wordpress gives feeds for tags in local wordpress sites. for example, there is a feed for the tag tamil at http://ta.wordpress.com/tag/tamil . But, could you give feed for the whole site http://ta.wordpress.com so we could keep track of all wordpress blog posts written in Tamil? Also, if you could publish an OPML of all the blogs written in tamil in wordpress we could make you use of that for various purposes. Say, people can try creating aggregators of different kinds for the content they get from language specific wordpress blogs.