Not at the moment, but I'm looking into ways to add it. Just appending the language to the query works well for SO posts, less so for the GH functions.
This is a very important feature. It’s not enough to have the user add more text to the box. I’m on mobile and it’s hard. There should be a toggle on every page prominently displayed that allows you to filter by programming language. Its the reason I came here to comment after trying to make it useful for me. I actually really like this!