use pythons locale package to determine the system locale

src/i18n.py

@@ -4,9 +4,10 @@ from pathlib import Path
 
 from src.pluginregistry import PluginRegistry
 from src.settings.settingsstore import SettingsStore
+from locale import getlocale
 
 settings = SettingsStore.load()
-locale = os.environ['LANG'] if 'LANG' in os.environ and os.environ['LANG'] else "en"
+locale = getlocale()[0]
 locale = settings.session.get('general', 'lang', fallback=locale)
 
 _ = False
@@ -24,4 +25,3 @@ if not _:
     _ = gettext.gettext
     ngettext = gettext.ngettext
     PluginRegistry.execute("set_locale", '')
-    print('No translation found')