Python is the most popular programming language used at Google for various purposes such as web development, machine learning, and data analysis.
Java is another widely used programming language at Google, especially for developing Android apps and building large-scale distributed systems.
C++ is preferred for developing high-performance applications and systems, such as Google Chrome and Google File System.
Go is a relatively new programming language that is gaining popularity at Google for its simplicity, concurrency, and scalability.
JavaScript is used extensively for front-end web development and building interactive user interfaces for Google products such as Google Maps and Google Docs.