Good afternoon, all. 
Just a quick question. I had until now thought that I could substitute te pros+acc idea by adding the δε particle to words, as in οικαδε or Αθεναζε (to conjure memorized examples), but I was told today that those expressions are only themselves true, given that they cristalized in that way, and thus remained in use, but that it is generally impossible to use the process in other words. Which one is correct?
Thank you in advance.
Miguel