[kovidgoyal]

First for language, you want:

if language[0] in ("pt_BR", "pt_PT", "pt")

more generally speaking you can eventually setup proper translations for the plugin, via Transifex.

Now for the config dialog , you have to link up the config menu item to some code to actually open the dialog, like this, in main.py:

    def do_config(self):
        from calibre.gui2.widgets2 import Dialog
        from calibre.gui2.tweak_book import tprefs
        from PyQt5.Qt import QVBoxLayout
        from calibre_plugins.ACE.config import ConfigWidget
        tool = self

        class ConfigDialog(Dialog):

            def __init__(self):
                Dialog.__init__(self, 'Configure ACE', 'plugin-ace-config-dialog', parent=tool.gui, prefs=tprefs)

            def setup_ui(self):
                self.l = QVBoxLayout(self)
                self.w = ConfigWidget()
                self.l.addWidget(self.w)

            def accept(self):
                if self.w.validate():
                    self.w.save_settings()
                    Dialog.accept(self)

        d = ConfigDialog()
        d.exec_()

link it up to you action like this:

            config_menu_item.triggered.connect(self.do_config)