I try to use my native language: Chinese.
It doesn't show up.
English can be displayed.

Utf8 supports Chinese, why so?

Also, make sure that the input text really is in utf8 format. If you use visual studio, constant C strings will normally not be utf8. Try to read the string from a file in stead.

Input text here refers in a very general way to any string that you might display in your program.

This string could either be generated by your own program or input by the user through some sort of textbox you design.

Unfortunately, normal C-style strings are not really UTF-8 compatible. It just so happens that normal English characters map to the same values in both ASCII and UTF-8 encodings.

Yeah... I figured that might be part of the issue.

Still, UTF-8 is somewhat complicated to understand at first. Many pieces need to be fitted in the correct order and way for it to work as intended.

C strings are 1 byte, UTF-8 needs much more to store the larger numbers.

Allegro has UTF-8 functions. Also, the IDE you use to program with may need to have UTF8 enabled. I don't know about Visual Studio, but with Code::Blocks you go to SETTINGS->EDITOR and under the ENCODING SETTINGS tab you can set the encoding it uses to UTF-8.

Notepad++ also has a similar option. I use it sometimes as well. I would imagine Visual Studio has such an option, I just wouldn't know where.

In my Deluxe Pacman 2 game, which supports UTF-8, I use functions in my Highscore routine like:

al_fread32le() to read in names etc... from the high score file.
al_ustr_new_from_buffer() etc...

here's a short snippit from my highscore function which reads in names from the file...

cstrsize = al_fread32le(hiscore_file[i]);
cstrname = (char *)malloc(cstrsize);  // allocate memory for name
if(cstrname == NULL) {
   al_fclose(hiscore_file[i]);
   printf("%s(%d): memory allocation failed.\n", __FILE__, __LINE__);
   return true;
}
al_fread(hiscore_file[i], cstrname, cstrsize);
// assign the c string to the ustr variable from buffer
hiscore[i][j].name = al_ustr_new_from_buffer(cstrname, cstrsize);
free(cstrname);

And my hiscore[].name is an ALLEGRO_USTR variable.