I presume you are talking about switching between locale, i.e., changing to Chinese input or other language input. I do not experience any problem with that. Can you be more specific about your system setup? perhaps then we can find something that’s not in place.
The info you are providing is really not enough for ppl to help you. pls tell us more thing like, the config of you system, what kind of other security software are you using, like AV, Antispy etc. Are you using the standard input locale provided by MS (like attached diagram) or some third party stuff etc etc…
CPF with Defense + should not interfere with the language change. I have been using it with Defense+ without any such problem related to switching between different input languages.