For each native platform, there actually aren't many (viable) choices. Android has Android (framework) and Java. iOS has iOS (framework), and a choice between two very similar and interoperable languages, Objective-C and Swift.
If you decide to go HTML5 cross-platform you have Phonegap vs. other web wrappers (wrappers); Ionic, Famo.us, Sencha, hand-rolling-your-own (frameworks); and finally just JavaScript (language).
This is ignoring other cross-platform things like Xamarin (which consists of Xamarin the framework, C#, and still also the iOS or Android frameworks, depending on your targets), Titanium, etc.
If you decide to go HTML5 cross-platform you have Phonegap vs. other web wrappers (wrappers); Ionic, Famo.us, Sencha, hand-rolling-your-own (frameworks); and finally just JavaScript (language).
This is ignoring other cross-platform things like Xamarin (which consists of Xamarin the framework, C#, and still also the iOS or Android frameworks, depending on your targets), Titanium, etc.