If you consciously are able to understand what you have written in English then your non-conscious mind can handle it. In fact the non-conscious part of your mind is far more capable of understanding and learning it than your conscious mind.
So a basic fluency is all you need to use the Paraliminals. I've had someone tell me their non-English speaking friend has had benefit from Self-Esteem Supercharger I think that's probably because incidently everyone is exposed to a smattering of English and the non conscious mind understands it on a "need to know" basis. Listening a few times is like learning the language too. Like when you were a child you learned the language by repeatedly hearing words in you native language.
Alex