What language does operating systems use?

Operating systems are primarily written in low-level programming languages like C and assembly language, which provide direct hardware access and efficient performance. C is particularly favored for its balance between control and portability, allowing OS developers to write code that can run on various hardware architectures. Some components may also be implemented in higher-level languages like C++ or Python for specific tasks or utilities, but the core system typically relies on lower-level languages for critical functionalities.