Does anyone know when and/or where they first said that dragons cannot speak in their draconic form?

I was looking through Bottled Demon, and a western dragon speaks to the players while in draconic form and with no mention of it being telepathic or line of sight.

I also did not see this detail in the dragon rules in SR1 or SR2.

So did I just miss a reference, or did they take draconic form physical speech away at some point?

I want to say the FASA dragons booklet. It's also explicitly called out in Dragons of the Sixth World (p. 18).

Well, there is "Dunkelzahn: The Mass-Media Dragon" which touches on the problem.

http://old.shadowrun4.com/fiction/fiction3.shtml

It was originally published in Dragon #199, quick search says that was 1993.

Couldn't they just use Dragon Naturally Speaking?

Only if they spoke with a US Accent. Bloody thing was impossible to train for my speaking style. Nine months of trying and just getting more and more frustrated.

A dragon probably has the physical manipulation magical chops to make whatever sounds he wants propagate through the air, including speech. If he then combines that with opening and shutting his jaws in something that approximates the sounds he's making, well, there you go, the dragon is talking. Better listen to what he says or call in an air strike.

Eee-le-ven.

It says it in the 3rd edition Core book. You are right it isn't mentioned in the 2nd edition Core book.