QMessageBox перевод кнопок

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QTranslator qtTranslator;
    if (qtTranslator.load(QLocale::system(),
                "qt", "_",
                QLibraryInfo::location(QLibraryInfo::TranslationsPath)))
    {
        qDebug() << "qtTranslator ok";
        app.installTranslator(&qtTranslator);
    }
    QTranslator qtBaseTranslator;
    if (qtBaseTranslator.load("qtbase_" + QLocale::system().name(),
                QLibraryInfo::location(QLibraryInfo::TranslationsPath)))
    {
        qDebug() << "qtBaseTranslator ok";
        app.installTranslator(&qtBaseTranslator);
    }
    QMessageBox::question(0, QObject::tr("Sure want to quit?"), QObject::tr("Sure to quit?"), QMessageBox::Yes | QMessageBox::No);
    return app.exec();
}

Упрощенный пример:

QMessageBox messageBox(QMessageBox::Question,
            tr("Sure want to quit?"),
            tr("Sure to quit?"),
            QMessageBox::Yes | QMessageBox::No,
            this);
    messageBox.setButtonText(QMessageBox::Yes, tr("Yes"));
    messageBox.setButtonText(QMessageBox::No, tr("No"));

Источник: https://stackoverflow.com/questions/31533019/title-qt-how-to-translate-the-buttons-in-qmessagebox/31533126