If it is interpreted or bytecode language, it needs an interpreter or virtual machine, one per process eg one per one command line window.
In many languages you can from main programme call other language programmes if these second are translated to native binary code.
It is possible to run programs in different languages each in different processes (eg window), and let communicate it eg with shared files, or with a net protocol.
Yes you can use multiple programming languages to create a piece of software. It's known as mixed language programming. However, in most cases each language must be in a separate file.
There are some exceptions to this e.g. you can embed assembly language in C/C++ code; and the Windows Scripting Host can handle multiple scripting languages in a single file.