Smooth talking and suave Stefan was the alter ego of nerd and clumsy to the hilt Steve Urkel. It must have been a strain on Jaleel to use the Urkel voice all the time, this dual role could have helped him give that voice a rest.

I think that his Stefan voice was his real voice. If I recall correctly that's how he sounded when I saw him on The Arsenio Hall Show and his The Fresh Prince Of Bel-Air guest appearance.

It is because its true Stefan's voice was more cooler than Steve's

Yes, that is his real voice.

God bless you and him always!!!

Holly