There is considerable debate about the position and appropriate terminology for the varieties which are spoken in Scotland. Scottish English can be described as a bipolar linguistic continuum, with Broad Scots, essentially a spoken variety, at one end and Scottish Standard English at the other. This continuum is the result of dialect contact and language change over many centuries. Four main dialect divisions of Scots can be distinguished whose names reflect their geographical distribution across Scotland: Mid or Central Scots, Southern or Border Scots, Northern Scots, and Insular Scots. Scots is generally, but not always, spoken by the working classes while Scottish Standard English is typical of educated middle class speakers. It is probably fair to say that a good proportion of the population of Scotland, now estimated at some 5,060,000, are potential speakers of Scottish Standard English. Defining the number of speakers of Scots in Scotland, however, is extremely difficult.