Stephan K?mper wrote:

> Now, that leads me to a question: _Should_ accented letters be matched 
> by [a-z]? I personally am not sure whether it does...

Well if your locale was french then you would expect the accented 
characters to match those used in french but it should ignore the 
icelandic thorn of the dutch y umlaut thingy.

So the answer is depends, and it depends on locale.