Why is using more than one language in application server projects?
After a while surfing on source code of big projects especially application servers like [this][1], I have understand these projects are not developing by one language. Many of them are using python for secondary language.

Now I have four questions: 

 1. Why is used more than one language?
 2. Why python is used for secondary often?
 3. Why python is not used to develop all parts of projects and they still is using c/c++?
 4. And which the parts of projects should be developed with python and which part of projects is using c/c++?
  

  [1]: http://www.cherokee-project.com/contribute.html
Why is using more than one language in application server projects?
===

After a while surfing on source code of big projects especially application servers like [this][1], I have understand these projects are not developing by one language. Many of them are using python for secondary language.

Now I have four questions: 

 1. Why is used more than one language?
 2. Why python is used for secondary often?
 3. Why python is not used to develop all parts of projects and they still is using c/c++?
 4. And which the parts of projects should be developed with python and which part of projects is using c/c++?
  

  [1]: http://www.cherokee-project.com/contribute.html