It's about the meaning of the words you use, and that she uses, right? So can you try some kind of semantic feature analysis? That's a surprisingly effective way to find out when you are using words in a different way from the person you're talking to. (A simple introduction to SFA is at http://edweb.sdsu.edu/triton/guides/SFA.html )

For me, what worked was to change the language; though I did it mostly so I would be better able to speak myself, it also means that I understand T better, I think.