FOSS gamedev and creative worlds

I'm currently trying to design a subgame that uses a language that contains accented characters. However, when I use accented characters directly in the description string, the mouseover text becomes "<invalid multibyte string>" instead of, for example, "Ŝtono (Stone)". Is there a way to set the mouseover text that allows Unicode characters to be used or am I just out of luck?

I may be wrong, but I heard this is an unsolved problem, Minetest doesn't support accented characters (I don't know the problem exactly). This is a very big problem for me too, I tried to write accented characters to signs, and those characters just don't appear.
I hope it will be fixed in the future.

This might be a problem with the irrlicht engine.

For the longest time I had troubles in Minetest with the input. I was not able to type any single thing anywhere (I even couldn't type world names or world seed names properly, so couldn't create a world) only typing somewhere else and copy-pasting it did it work.

Then, after having abandoned minetest for a long time in that PC, I discovered the issue was that my system was set to "English (Malaysia)". When I changed the language to "English (United States)" it worked perfectly.

How about sorting out specific characters before putting them to irrlicht?