High quality results need painting by hand. That's slow and difficult, but something a little resembling can be achieved by crafting manually normal text to a less perfect shape. A quite simple font must be used to keep the job easy. An example(Photoshop):
the original text, rasterized onto white background, it's not a separate layer because the white is needed to prevent edge transprency in step 3.
random white is scattered on the text.
the characters are smudged along their strokes using a brush with multiple dots. No preset effects follow the strokes, so this must be done manually. A programmer could have written something automatic, but I haven't it. Try different smudging strengths.
the result is posterized to 3 colors
another attempt starting from the same image 2, slightly different smudging
Why the posterization? It makes white color exact. White areas are easy to select and delete. Generally the result becomes also sharper.
The detoriated text itself (after inverting) can be used as a layer mask for the final color. An example:
In Illustrator one can find the skeleton of the text an replace in it the normal solid strokes with a pattern or artistic brush. That brush obviously must be made for this purpose. Making a custom brush from scratch or from a scanned real brush stroke is another story. We use only presets here.
This subjent is presented in another answer. I admit all what is told there, but I still tried it. See the cartoon:
1A. The original text
1B. Outlined, given a thin stroke, no fill, groups and compound paths are all released. All characters were inspected individually after founding that single selection was not enough.
2A. Inner loops have got positive offset strokes
2B. Outer loops have got necative offset strokes
3A. All unnecessary which were selectable with the normal selection tool, are removed
3B. More unnecessary is deleted with the direct selection tool. The vertical stroke of K was edited to one piece.
4 and 5: Two different brushes are tried. B had two parts which needed manual alignment because the strokes are not uniforml.
I found the result is substantially better than what I got simply painting with the mouse over a piece of text. I'm sure that it could be much better, if the brush were custom made and there were 2 of them for different directions.
Another method in Illustrator is to rasterize the writing and trace the result. After expanding the trace a brush can be applied.
Illustrator's Live Trace has an option to trace the strokes. If one allows thick enough stroke, he really gets the skeleton, but it has many extra twists, as the following screenshot shows. The twists can render the method useless for complex Asian writings, if the user cannot rectify the shapes with the direct selection tool.
At its best this method gives quite same as manually digging out the skeleton and applying a proper brush. But it's easier even if some manual tunings are needed.
One can wonder why I offer methods this complex? Why I do not simply take the pen tool and manually draw the skeleton - a few clicks per character? Answer: Oriental fonts are not simple. Knowing it I tried to find some shortcuts. Tracing rasterized text as strokes and applying a brush is obviously the nearest, but its quality is very questionable without manual path editing.
Single line or engraving fonts? There are some that do not get thicker in any zoom. If you have one, you need only write your text, outline, adjust the size and apply a brush in Illustrator. Done. Unfortunately I have not a well implemented such font to show an example, but I found a link of the subject:
Such fonts are often good only in some special software, they do not obey all windows conventions. The result is distorted or partially invisible rendering in Illustrator. I tried CamBam Stick fonts (freeware). Illustrator left with them some lines invisible. The rest of the characters worked perfectly.