one basic question, I would like to know:
what programming languages are used to build Tor?
TBB include Firefox and other things, so, correct question is about Tor.
Tor itself is C. If you're curious about languages used in the wider ecosystem see...
https://www.torproject.org/getinvolved/volunteer.html.en#Projects
The core Tor library is written mostly in C.
You can check out the source code yourself here: