I’ve updated my grammar lessons for learning Tamil at https://www.learntamil.com . It should have a cleaner look, easier to view on mobile devices, and you can listen to the audio files because they’ve finally been converted from RealAudio format to a modern common format, MP3.
I started my Tamil grammar lessons 20 years ago as “Thamil Paadanool” (தமிழ்ப் பாடநூல் = Thamil textbook) at http://www.unc.edu/~echeran/paadanool. It was a way to create Tamil grammar lessons in the way that I believe they should be done for people in the 10+ age range trying to learn. About 10 years later, after I had to move the lessons to my other personal webspace at https://www.ibilbio.org/tamil/paadanool . A couple of years ago, I acquired learntamil.com and moved the lessons once more. Not much about the lessons have changed in the entire 20 years, but a few months ago, I did an update of the aesthetics and usability. So if you see PDFs or links floating around on the internet with the old unc.edu/~echeran address, or even if you haven’t, check out the new website address and pass it on.