No... my ideas aren't from NA/EDA... I haven't read any of that. I was thinking of Brain of Morbius, and that the Sisterhood of Karn are a magic-based culture, rather than scientific, also, the hints in Invasion of Time of a whole population of people who are not time-travelers. and are not in the elite... But presumably still speak the language of the planet.

And I had not heard that idea of Terrance Dicks and Barry Letts, either... I know just about nothing of background commentary (almost typed "background comedy," there... my Freudian almost slipped).

My (absolutely private) theory on Gallifrean is this: the very fact that time acts strangely around Gallifrey, thanks to the black hole at its core, the experience of time would be different for all Gallifreyans than it would be for an Earthling. So I always thought (not knowing the "mathematical formula can be a proper name" thing) that the language would be much more fluid than a human language, rather than more rigid.