@scy I don't think this is completely true. I heard both pronuncations in the late 70's and early 80's -- well before ST:TNG debuted. I don't think either one was prevalent here in the US.
However, I can believe that the Patrick Stewart pronunciation became the more favored form during and after ST:TNG.
@Unatributed I'm not exactly convinced either, that's why I've prefixed it with "according to Brent Spiner".