I want to design one robotics project so which language is to be used in?

Answer 1

The most popular language in robotics is probably C/C++ (C++ is an object-oriented successor to the C language). Python is also very popular due to its use in machine learning and also because it can be used to develop ROS packages

for more info:
https://www.futurelearn.com/courses/robotic-future/0/steps/29368#:~:text=The%20most%20popular%20language%20in,develop%20ROS%20packages%20%2D%20see%20below.

Answer 2

Aggred with Martin Taylor infact I also dont know about all fields of robotics. And your question talks about every field and you hadn't mentioned that you are beginner or professional I think beginner because if you would be professional you wouldn't have asked this question

So to understand robotics you might start from very small steps like from arduino it uses c/c++ language officially but you may use any like python too ("I prefer it")