I have a great two-minute teaching method to pronounce a certain digraph for ESL students. I just posted it on my new FB page and it is taking off like crazy. Someone is going to claim it as their own. Can it be pantented?
Very unlikely. To start, if you have exposed it to the public you have “broken novelty”. That means in almost all countries in the world is is too late to file. The U.S. has a sort-of one year grace period.
Unless your system involves an apparatus it is likely to be abstract or otherwise not patentable subject matter.
There are patents on teaching methods and devices. The number and title of a recent one is US10629093B2 Systems and methods providing enhanced education and training in a virtual reality environment.
This patent US3014286 from 1961 is for a device to help English speaker pronounce French words.