There has been a (low-level) stream of reports since years now, about users wanting to write in Blender in their own language, which requires [complex script layout](https://en.wikipedia.org/wiki/Complex_text_layout).
This is currently not possible in Blender, we only have a very basic/simple layout code. Some scripts (like Arabic one) can partially work around the situation by using (pasting) some kind of 'pre-processed' strings using pre-layed-out unicode points instead of the 'raw' ones, but this means people cannot directly type in Blender in those languages either. And this is not available for other scripts, like many from South-East Asia (India, Cambodia…).
Most obvious solution currently would seem to be to replace out current layout code with [HarffBuzz](http://harfbuzz.org/), probably together with [fribidi](https://github.com/fribidi/fribidi).
This is not a terrific amount of work, but likely not a very simple one either, and though most of it should be limited to the BLF area of the code, it could require some changes elsewhere too. First step would be to try a quick proof-of-concept, to see how well that could be going…
See also {D1809}, an old patch adding support to complex scripts.