Programming languages are formal languages used to communicate instructions to a computer. They consist of a set of rules and syntax that allow programmers to write code, which the computer can then execute. Examples of popular programming languages include Python, Java, and C++. Each language has its own unique features and is suited for different types of tasks, such as web development, data analysis, or software engineering. These languages can be categorized into high-level and low-level languages. High-level languages, like Ruby and JavaScript, are more user-friendly and abstract away complex details, making them easier for humans to read and write. Low-level languages, such as Assembly and C, provide more control over hardware but require a deeper understanding of computer architecture.