В 4.5 появилась интересная функция:
QString QTranslator::translate ( const char * context, const char * sourceText, const char * disambiguation = 0 ) const [virtual]
Returns the translation for the key (context, sourceText, disambiguation). If none is found, also tries (context, sourceText, ""). If that still fails, returns an empty string.
If you need to programatically insert translations in to a QTranslator, this function can be reimplemented.
This function was introduced in Qt 4.5.
Но к сожалению это не подходит для перевода чисел
Интересный комментарий кстати в qtranslator.h:
// ### Qt 5: Merge (with "int n = -1")
virtual QString translate(const char *context, const char *sourceText,
const char *disambiguation = 0) const;