This may exist but I can't find it

This may exist but I can't find it. I would like to see a search by languages used for the projects.

some projects write the used language in their tag list, the code-scanner could do that too, would be confusing regarding documentation formats (html) though.

Storing code language information in tags sounds redundant to me, as Ohloh already knows which languages are used in a project. That being said, it should be very well possible to get a list projects by their main language used based on the information Ohloh currently knows.