What are the languages required for creating the mobile operating system(OS)?

Question

creating the new operating system like windows, Android, mac etc

Answer 1

Generally low-level languages, in some cases could be necessary assembly.

C / C++ are basics, but you should learn something about hardware, memory, kernel and so on...

Made an OS from scratch is really hard, what do you think about Distro with the Linux kernel? Maybe something like "Debian-Based" distro's. :)

[ EDIT ] - Android is partially based on Linux. (Just for completess)