vbox:

                    style_prefix "radio"
                    label _("Language")
                    textbutton "English" action Language(None)
                    textbutton "Spanish" action Language("spanish")







The whole pref menu code:

screen preferences():

    tag menu

    use game_menu(_("Preferences"), scroll="viewport"):

        vbox:

            hbox:
                box_wrap True

                if renpy.variant("pc") or renpy.variant("web"):

                    vbox:
                        style_prefix "radio"
                        label _("Display")
                        textbutton _("Window") action Preference("display", "window")
                        textbutton _("Fullscreen") action Preference("display", "fullscreen")

                vbox:
                    style_prefix "check"
                    label _("Skip")
                    textbutton _("Unseen Text") action Preference("skip", "toggle")
                    textbutton _("After Choices") action Preference("after choices", "toggle")
                    textbutton _("Transitions") action InvertSelected(Preference("transitions", "toggle"))

                ## Additional vboxes of type "radio_pref" or "check_pref" can be
                ## added here, to add additional creator-defined preferences.




                vbox:

                    style_prefix "radio"
                    label _("Language")
                    textbutton "English" action Language(None)
                    textbutton "Spanish" action Language("spanish")



            null height (4 * gui.pref_spacing)

            hbox:
                style_prefix "slider"
                box_wrap True

                vbox:

                    label _("Text Speed")

                    bar value Preference("text speed")

                    label _("Auto-Forward Time")

                    bar value Preference("auto-forward time")

                vbox:

                    if config.has_music:
                        label _("Music Volume")

                        hbox:
                            bar value Preference("music volume")

                    if config.has_sound:

                        label _("Sound Volume")

                        hbox:
                            bar value Preference("sound volume")

                            if config.sample_sound:
                                textbutton _("Test") action Play("sound", config.sample_sound)


                    if config.has_voice:
                        label _("Voice Volume")

                        hbox:
                            bar value Preference("voice volume")

                            if config.sample_voice:
                                textbutton _("Test") action Play("voice", config.sample_voice)

                    if config.has_music or config.has_sound or config.has_voice:
                        null height gui.pref_spacing

                        textbutton _("Mute All"):
                            action Preference("all mute", "toggle")
                            style "mute_all_button"