Currently, there are millions of iPhone and iPad devices in the world, and numerous iOS apps are out every day. So, what language are iOS apps written in? When we look around, we see there are two major players, namely Swift and Objective-C. iOS apps can be written in other languages, too, if one wishes so. However, a lot of time-consuming adjustments will be needed since every language is not created specifically for the purpose. Hence, few are interested in such languages, except for specific reasons. None of them is eligible to be called a true iOS coding language. Some suitable languages include C#, Python and HTML 5. They are all far behind in popularity as compared to Swift or Objective-C as an iOS language, but they are still briefly mentioned below.
Swift is the default iOS app language for anyone embarking upon iOS coding. It was officially introduced by Apple in 2014 as its own language. Until then, Objective-C used to be the default Apple programming language. Swift is a general-purpose, compiled language and is an open-source software. Swift is told to be the Objective-C with the C stripped off, making it far easier to learn and flexible to use. It eases a lot of complications a developer comes across with Objective-C. Swift is designed to work with frameworks such as Cocoa and Cocoa Touch for macOS and iOS respectively. It still works with the existing Objective-C codes for the Apple devices, too. iOS apps of reputed networks such as Firefox, WordPress, etc., use Swift.
With the introduction of Swift by Apple, Objective-C became a less preferred iOS programming language. Objective-C is an Object-Oriented Programming (OOP) language that emerged in the 1980s. It is now used in association with several Object libraries which are themselves part of some operating system. In case of iOS, it works with Cocoa Touch framework. Like C++, C#, and the like, Objective-C was also derived from the C language. It was in fact an attempt to transform C to make it suitable for OOP. Its structure is essentially that of C, but with many things added on to it. Hence, one can easily insert C commands into an Objective-C program without disturbing it much. It used to be the preferred Apple coding language before Swift. Even though Swift is gradually pushing it back, it is still expected to be around for some more time.
C# was developed in 2000 by Microsoft and is a general-purpose, flexible and versatile language. It is not an iOS coding language per se but can do the job with the help of an intermediate tool like Xamarin. A C# programmer with no iOS coding knowledge can write in C# and Xamarin, compiling it to the native iOS binary code. Among other languages, C# also has inspired the design of Swift by Apple.
Python is an open-source, general-purpose language that supports Object-Oriented paradigms. Python can be helpful in creating resource libraries in iOS coding. Swift has also borrowed ideas from Python in its development.
HTML 5 is a markup language which can handle cross-platform applications. HTML 5 is not an Apple programming language as such; however, it can work in combination with CSS to create hybrid apps. Such apps can tie themselves up with intermediate programs to present pages in the iOS scenario.
As of today, Swift is the most preferred and popular iOS coding language. Behind it trails Objective-C whose importance is gradually fading away. And there are a few others in use for specific reasons. However, no language is permanent as newer languages always keep emerging to meet the changing requirements of time.