I first saw all the movies back in the late 80’s (in college), but I’ve only seen a handful of the 1974 “live action” tv-series episodes. But I managed to record the very first episode a couple weeks ago, and am just watching it today (and it’s been years since I’ve seen any of the other episodes - probably 5-6 total, a most, no idea which ones).

So, humans couldn’t talk in the original movies (at least the first 2), but now I’m suddenly remember they talk in the 5th movie.

Is there a time-line that helps explain?

I used to remember all this better, but it’s been 10+ years since I’ve dug into much of the original movies (at least that long since I saw movie #5 - the last movie before the tv-series).

(I’m NOT asking anything about the animated series.)