What programming languages can one use to develop

Possible Duplicates:
Which programming languages can I use on Android Dalvik?
Which programming languages can be used to develop in Android?

What programming languages can one use to develop Android applications?

Also are there plans in the future to expand the amount of programming languages that Android will support?

UPDATE: There are really good answers over here

Which programming languages can be used to develop in Android?

Here's a list of languages that can be used to develop on android:

Java - primary android development language
Kotlin, language from JetBrains which received first-party support from Google, announced in Google I/O 2017
C++ - NDK for libraries, not apps
Python, bash, et. al. - Via the Scripting Environment
Corona- One is to use the Corona SDK . Corona is a high level SDK built on the Lua programming language. Lua is much simpler to learn than Java and the SDK takes away a lot of the pain in developing Android app.
Cordova - which uses HTML5, JavaScript, CSS, and can be extended with Java
Xamarin technology - that uses c# and in which mono is used for that. Here MonoTouch and Mono for Android are cross-platform implementations of the Common Language Infrastructure (CLI) and Common Language Specifications.

As for your second question: android is highly dependent on it's java architecture, I find it unlikely that there will be other primary development languages available any time soon. However, there's no particular reason why someone couldn't implement another language in Java (something like Jython) and use that. However, that surely won't be easier or as performant as just writing the code in Java.