All three main languages of Switzerland have two sets of personal pronouns. The most useful for business usage is the formal form (Sie, Vous and Lei), but you may encounter the informal forms, du, tu and tu used within families and close friends. If an acquaintance offers to switch to the informal form, that is a sure sign of a personal relationship beginning. However, you should not expect it before much time has passed and in any case you should never propose it yourself. In German-speaking Switzerland, you should address men as Herr Bucher, or Frau Bucher for women. People who hold a doctorate should always be called Herr Dr. Schmidt, and if you meet a University Professor (this commands much prestige in Switzerland) you are expected to use Herr Dr. Professor Zaehringen. In the French-speaking part, people are usually addressed as Monsieur or Madame. Attorneys of both sexes will be offended if you do not call them Maître (literally: Master), and those who spent years writing a thesis will be grateful for a Dr. Supersaxo. Finally, people in Ticino have taken the taste of their Italian cousins for exaggeration, and people who hold any degree should be referred to as Dottore Casanova. For the rest, Signore or Signora will do.