There are 7 main programming languages for mobile apps: JavaScript, C++, Python, Objective-C, Java, PHP, and Ruby on Rails.
JavaScript: If your mobile app will be used across multiple platforms and via the web, JavaScript is a powerful language that offers a great deal of flexibility. It's easy to work with, is used by many developers, and is relatively fast.
C++: A capable, object-oriented language, C++ is often used for Android apps and is ideal for developing games, GUI-based applications, and cloud computing apps.
Python: A programming language suitable for desktop apps, machine learning, and media tools, Python delivers a great deal of flexibility for creating mobile apps. It's also fast, easy to use, and can be deployed relatively quickly.
Objective-C: Mainly used for iOS and macOS app development and operating systems, Objective-C is a general-purpose, object-oriented language that is easy to learn for most developers.
Java: The official Android development language, Java is an excellent, object-oriented language with built-in open-source libraries. It’s easy to work with and offers excellent documentation, along with good community support.
PHP: A highly-recommended programming language for mobile apps, PHP offers great database access and is ideal for e-commerce applications.
Ruby: A back-end, object-oriented scripting language, Ruby is successfully used to develop web applications, servers, and system utilities. Users find it easy to maintain and say it offers smooth performance.