Which Language used in writting OS

[vishparshav1]

I have started with the course. I know its very early to ask but i have a really big doubt lingering which is haunting my nights.Can anybody help me with telling which language we will be using to write the OS. Correct me if I m asking the question in a wrong way or even the question is wrong but i need help on this big time.
Thank you
Plz somebody reply asap on my mail [e-mail]

[ybakos]

You will use the Jack language to write this.