Thanks for the link, very interesting indeed.

In my case, though,I could hear a few words the first time I listened to the sine-wave modulated version. It became much clearer after listening to the primer, though.

Sadly, once you've heard the primer, you can't really go back to hearing it the way you heard it the first time, so you can't compare back to back. It's a bit like "hidden" messages in songs; once you hear them, it very hard to revert back to hearing the original lyrics.