Need help in programming

I want to program an application for an android phone and I have a few questions here:

What programming language should I use? (C++? or are there better?)

Specifically my application is sign language recognition.
I will use an android phone for capturing motion images.
I will put five distinct color in each finger and after capturing images, the application will process those images using the given colors and then compare it with a given database.

Can anyone give me an idea on how i should do this?

Start here.. https://developer.android.com/sdk/index.html

Download eclipse.... And use the emulator... (You need a Dual core at least).

There are examples in the SDK