Before cancelling the possibility of using images, you can still use some JavaScript to replace certain characters with equivalent images, which would be easier than arranging a bunch of images in the editor.

Now, another possibility is to import a font that includes the language that you want (using the CSS @font-face rule), which would work best with a WOFF font file (see table here).
Perhaps there are also certain fonts that let you take ordinary english characters and display them as if they were in that other alphabet, kinda like icon fonts.

*edit* actually, when i think about it, the JavaScript solution might not be suitable for tablets and smartphones.

The character map on the system tools work well, thanks