Sylvia:
Great question!
Creative Commons licenses are carefully developed by legal staff to work hand-in-hand with copyright law. Copyright law varies from nation to nation. Variations in copyright law have historically required Creative Commons licenses to be "ported" or adapted to particular nations to ensure legal accord.
When you are using the Creative Commons license chooser you can specify what nation you are from when choosing a license from the License Jurisdiction drop down menu. You'll see a large number of options (55+) available.
Creative Commons operates a wiki with extensive FAQ support. Others have asked a similar question. This link takes you to the FAQ answer to your question and provides another link to "considerations you may wish to take into account before choosing an international or a ported license".
Creative Commons is just about to release version 4 of its licenses. A major effort in designing and developing the Creative Commons Version 4 licenses has been internationalization of the license language so that the default license addresses the needs (both legal and cultural) of users in all jurisdictions. To successfully accomplish the goal of internationalization Creative Commons engaged in a major collaboration with all of our CC affiliates around the world (+70) as well as participation of our broader community of users. We're excited about the international nature of the resulting licenses.