It's different in Germany and Italy, and elsewhere as well, I presume. In Germany right now, I'd be a Doctoranda, a perfectly good title to denote my current progress towards earning this degree. Once the degree is achieved, I would legally be referred to as Doktor. The language would not confuse me with a medical doctor. The title legally required is clear under the circumstances. In Germany, a university level teaching position comes with the title "Herr Professor Doktor" (for men).
In England, it's different. The word "professor" is reserved for university instructors who hold endowed chairs. The title denotes a much higher status within the hierarchy of academia than it does in Canada and the U.S., where any university instructor can be called a professor without too many people making a fuss over it. (To be fair, many will still argue that one should at least hold a PhD in order to deserve the title). University-level instructors are Lecturers or Readers in a specific area, and addressed as Ms. or Mr. In the U.S., Mr. or Ms. as a title usually means that the person in question does not hold a PhD, and, odds are good, that they are specifically teaching at a primary or secondary school.
In Germany, I would be Doctoranda Worthen right now. My students have called me Professor Worthen all semester, which is appropriate only in the sense that I was the course instructor - I don't hold the degree yet, and if I were working in England, it is quite likely that I would never hold a position which would make me eligible to be referred to as Professor. I don't know where I will end up working - possibly some other country entirely that the ones where I know anything about titles, the ones I have mentioned here. (Although if any of you know more about titling in these or any other countries, I would love to know more.)
It's strange to think that this semester, before I even have a PhD, could be the last time I will ever be referred to as a professor.
