Voice recognition without module, is it possible? I'm trying to figure out how to process a voice signal for simple purposes. Wherever I look people using or suggesting recognition modules for Arduino. 

What I'm wondering: is this possible to make a simple command recognition with Arduino, without modules? 

I just simply want to attach a microphone to my Arduino and after I convert it I want to handle signal and program it in MATLAB or in an Arduino itself. How can I achieve that?

As you can see I'm newbie in this. Any help is appreciated. Thanks!
No, it's not possible. The Arduino is not powerful enough to run the algorithms needed.

You need something with far more processing power, memory and storage. Something like a Raspberry Pi, maybe, or a desktop PC.

Or just use one of the many commonly available VR modules you can buy on the internet for next to nothing.