Updated the string manipulation texts to be prefixed, allowing for better context management if needed for things like "Effects", "System Effects". Added en translations to handle them on the English side. Updated the zh translations using merge:

`msgmerge --update locale/zh_CN/LC_MESSAGES/lang.p o locale/lang.pot`

gui/app.py

@@ -62,7 +62,7 @@ class PyfaApp(wx.App):
         if lang in supLang:
             selLang = supLang[lang]
         else:
-            selLang = wx.LANGUAGE_ENGLISH
+            selLang = wx.LANGUAGE_ENGLISH_US
 
         if self.locale:
             assert sys.getrefcount(self.locale) <= 2