That's really fascinating (sorry again for continuing the offtopic). I found terrific websites with dialect samples. I found out that in Kerkrade people even sound much more like Kölsch than in Maastricht, listen to this one (click on 'afspelen'):
http://www.meertens.knaw.nl/ndb/soundbites.php?p=Q121pThis is the general website:
http://www.meertens.knaw.nl/ndb/gmaps.php?t=nl