Namespaces can be both a blessing and a curse. As a beginner, you may tend to want to organize too much via namespaces. I advise everyone to use namespaces as sparingly as possible and only in a very flat hierarchy. This hierarchy should be based on properties of the pages that are unlikely to ever change.
There are much better and especially more flexible ways to group and organize pages, such as the Tag plugin.
Wikipedia can serve as a reference, for example: There, all normal topic pages within a language version are within the same namespace.
- Michael Sy.