First, I would like to emphasize that this post ain't about just software, but rather about a ready-to-go web service, preferrably free one.
Second, I am fully aware that RSS and atom would normally include an identifier which would allow anyone to determine the language of an original post.
However sometimes RSS feeds are generated from websites that don't offer a native support for RSS. For instance, the academia.edu website doesn't support RSS at this point of time, but I am still able to generate RSS from the following example links: https://www.academia.edu/Documents/in/Content-Based_Image_Retrieval/MostRecent https://www.academia.edu/Documents/in/Early_Christianity/MostRecent
I do it by using some other 3rd-party web-service. The problem I've encountered is that sometimes the above links include posts in different languages. Unfortunately, I don't read in all of those languages. So ideally I'd love new posts go through some other 3rd-party engine which would process all posts and tell me what language they are in before I upload each of them into my RSS reader. So basically I am looking for a very specific type of RSS filter. If anyone around here is in the know, I'd appreciate your help on that.