In the Italian language, there are three forms in which you refer to other people: [Lei], [Voi] e [tu]. This use is defined [darsi del Lei], [darsi del Voi] and [darsi del tu]. The tu form corresponds to the second person singular of the verb and is usually used when speaking to someone we know very well or are familiar with. The Lei form, on the other hand, corresponds to the third person singular while the Voi form corresponds to the second person plural. Unlike the tu form, both Lei and Voi are used in situations where the expression of respect is desired. The Voi form, however, is considered outdated and, almost, out of style. The use of these forms depends on different factors such as age, professional context, social condition but most of all, the degree of familiarity between the speaker and receiver. The question as to which form to use is completely up to the speaker, however it is important to remember certain points: adult strangers always greet each other with Lei.; elderly people are addressed with the Lei form until they ask to be addressed with tu, which usually means that they want to be called by their name; at work, people with the same weight in position address each other with the tu form but with someone in a superior position, the Lei form is always expected. Finally it is customary for people over sixty years of age to use Lei when speaking to each other as a common sign of respect. Nowadays, in Italy, people pass from the use of Lei to the tu form very quickly especially amongst teenagers. It is, therefore, important to remember that when the tu form is used unexpectedly or out of context, it may be interpreted as a lack of respect. It is comparable to addressing someone that you don't know well by their first name.