Implement of a vocal interface

Hello all.
It´s the first time i post on a forum so if i do a mistake please correct me.
I’m a student working on a project of robotics and as i’m a complete beguinner in robotic …
I work on the arducopter structure, using the Ardupilot Mega associated with the Ardupilot IMU as my autopilot board. I have an EasyVR module with an Arduino UNO to make my vocal recognition stuff.
But i don’t know how to give order to the autopilot board with my vocal module. Do i need to change the arducopter source code ? Do i have to use Mission Planner software ?
The final aim is to approach this : … lled-drone
I’m a little bit lost. If some one can help me…
Thank you.

Ps: sorry for my bad english