Can you get the Ed visa for studying other than the Thai language?

Unless things have changed over the past few years, the answer is yes.
I studied spoken Mandarin Chinese in Phuket about 5 years ago, and had no problems getting an ED visa to study at the licensed language school.
However, when I went to renew that ED visa at Phuket Immigration, they said I would have to do a language test. I explained that I was learning Chinese, and did they have a Chinese speaker in their office. They replied that they didn’t and so they would do the Thai language test with me!! Luckily, I already spoke Thai to a good level, so I passed the language test and got my new ED visa/visa extension…