NYSwifty conference
A Brand-New iOS Conference in New York City
Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. It's most commonly used for developing iOS, iPadOS, macOS, watchOS and tvOS application.
Apple intended Swift to support many core concepts associated with Objective-C, notably dynamic dispatch, widespread late binding, extensible programming and similar features, but in a "safer" way, making it easier to catch software bugs; Swift has features addressing some common programming errors like null pointer dereferencing and provides syntactic sugar to help avoid the pyramid of doom. Swift supports the concept of protocol extensibility, an extensibility system that can be applied to types, structs and classes, which Apple promotes as a real change in programming paradigms they term "protocol-oriented programming".
Source: Wikipedia
Swift is the programming language used to develop iOS applications natively. We prefer Swift over Objective-C for reasons mentioned above.