The best programming language for building Android apps is Kotlin. Officially endorsed by Google, Kotlin offers modern syntax, enhanced safety features, and full interoperability with Java, making it a popular choice for both new and experienced developers. It simplifies many common coding tasks, improving productivity. Java remains widely used and has a vast ecosystem, but Kotlin’s concise syntax and expressive capabilities often lead to cleaner and more maintainable code. C++ with the Android NDK can also be considered for game development or performance-intensive applications. Ultimately, the choice may depend on specific project requirements and developer familiarity.