Filtering loop using drop-down menus

I’m trying to figure out how to use two drop-down menus to alter a loop. I was wondering if there’s a way to do this in real-time. Ideally, I would have a loop displaying a list of posts, and I want to sort them by language and topic. I have language set in a custom field, and the topics are set as tags. I want the user to see the two menus at the top of a paginated loop, and if they select a specific language, then the loop would filter to show only posts with that language set in the custom field. If they select a topic from the other menu, it would further filter to show only posts on that topic. Any ideas on how to accomplish this? Is it even possible? Thanks.