Which programming language is used at Google, Microsoft or in any tech giant?

Google uses:

C++ for most backend code (think about search, ads, Gmail, etc)
Java for most frontend code (think about Google . com website itself) and of course Android
Python for testing automation and machine learning, and YouTube
And many other languages, for smaller usage.

My Microsoft knowledge is 10+ years old, so take it as a grain of salt:

All sorts of languages. The main reason is Microsoft is much older and has seen a generation of languages.
When I was there (2003 - 2006), my team uses a mix of:

C++
C# (then new hotness)
SQL

I personally found Google code base has more discipline than Microsoft code base, and at the same time, the entire Google code base is pretty much open to every engineer, while Microsoft internally was full of guarded walls. (For example, I didn’t even get read permission to Windows code.)

There is a reason why Google took over the tech innovation torch from Microsoft back then.

(The Last mention, Microsoft seems to be back on good innovation trajectory recently, which is a very good sign.)

Yunkai Zhou, Co-founder & CTO at Leap.ai; former 10-year Google eng lead