Ireland's education system is quite similar to that of most other western countries. There are three distinct levels of education: primary, secondary and higher (often known as third-level or tertiary) education. All children must receive compulsory education between the ages of six and fifteen years. English is the primary medium of instruction at all levels, except in Gaelscoileanna schools in which Irish is the working language and which are increasingly popular. Universities also offer degree programmes in diverse disciplines, taught mostly through English, with some in Irish. Most expats let their children attend local schools, there are, however, also a few international schools.