C

Designed by Dennis Ritchie in 1972 at Bell Labs, it gave birth to Unix and drove the rewrite of that operating system into a portable form. Over 90% of the world's operating system kernels—including Linux, Windows, and macOS—are built directly in C or its close derivatives, making it the bedrock of modern computing. This language defined the paradigms of memory management, pointer arithmetic, and low-level hardware control that subsequent languages have either adopted or deliberately avoided. Because of its efficiency and direct hardware access, C outperforms the average modern language in execution speed and memory footprint, powering everything from embedded microcontrollers to supercomputers. Without C's rigorous foundations, the entire software ecosystem—including Python's CPython interpreter and Java's JVM—would not exist as we know them.