Ian is a Scottish name. It is the scottish form of John. If you look at the German form of John which is Johan or Jan with the "J" pronounced as a "Yah" rather than the harsher "Dj" then you can see how John has migrated into Ian.

The Irish version of Ian is Sean, again you have to go back to John and play with that in your mouth a little to get to Sean.

In Wales it is not uncommon to see Ian spelled with two I's Iain, they pronounce it as, well I don't know how to phonetically spell how they pronounce it, but half a pint of phleghm in your throat usually helps when trying to pronounce Welsh.

Ian is also my real name.