Multiple Programming Languages

[Michael641]

How do companies like Facebook and Twitter use multiple programming languages in their applications?

 

[rgd1101]

by integration? Not exactly understand what you are asking for.

 

[Alabalcho]

You use the tool most appropriate for the job. Even if all the parts of s (big) application are written in same language, they often communicate between themselves using some kind of message protocol. When you have multiple computers, multiple languages, then this is the norm.