No useful physical keyboard--not even one specifically designed for multilingual work--could possibly contain a key for every character we would ever wish to type. Certainly there are characters commonly used in other areas of the world that are not present on most USA keyboards. So methods have been invented that provide for input of almost any known character on even the most naïve keyboards. These schemes are referred to as input methods (IMs).
Input methods vary significantly in design, use, and behavior, but there is a single API that developers use to access them. The object is for the application simply to ask for an IM and let the system check the locale and choose the appropriate IM.
Some IMs are complex; others are very simple. The API is designed to be a low-level interface, like Xlib. Usually, only toolkit text object authors must deal with the IM interfaces. However, some applications developers are unable to use toolkit objects, so the concepts are described here.
OpenGL does not contain input code but leaves that to the operating environment, which in IRIX means X.
In short, support for internationalized input means a departure from qread(). Under IRIX, that means using mixed-model input, all the more reason to use a toolkit.