Dear Mr. Leon Lu.
The problem is simpler as you can imagin. I think that it is possible to include in the APK file the variuos TEXT files. Probabily is possible include them as Resources.
For the stressed caracters I remember you that Android don't have a Unicode like Windows and the results are umpredicable but I think to overcome this problem using the capabilities of Android. Il old MSDOS there were the codepages and in Android there is the possibility to load different languages. For example I am using the format ISO-8859-1.