Education in Switzerland is very diverse because the constitution of Switzerland delegates the authority for the school system to the cantons. There are both public and private schools, including many private international schools. The minimum age for primary school is about six years in all cantons, but most cantons provide a free "children's school" starting at four or five years old. Primary school continues until grade four, five or six, depending on the school. Traditionally, the first foreign language in school was always one of the other national languages, although in 2000 English was introduced first in a few cantons. At the end of primary school (or at the beginning of secondary school), pupils are separated according to their capacities in several (often three) sections. The fastest learners are taught advanced classes to be prepared for further studies and the matura, while students who assimilate a little more slowly receive an education more adapted to their needs.