MonoTouch iOS FLAC File Speech Recognition

问题:

I'm programming an App for iOS which should recognise the human user speech with MonoTouch. I need to use the microphone and convert the Voice-File into FLAC format, in order to send it to the Google Speech API. Are there any Libraries/Code examples, or is it possible to build a Speech-Recognition App for iOS using MonoTouch and for example the Google Speech API? Or is it possible to convert the audio Output(a .caf file) to a .flac file?