Are droids cyborgs? Could Darth Vader be considered a cyborg? Is Luke a cyborg after getting his artificial hand? Why would cyborgs need to have a lame-ass droid as intermediary with humans anyway?
Luke and Vader are cyborgs in the textbook definition but I don’t see how there would be some intermediary needed between cyborgs and humans. Don’t forget though that 3PO is programmed for protocol and ettiquette. With all the different species throughout the galaxy plus the binary droid languages, there’s a big need for an interpretter. Still, “human/cyborg relations” doesn’t sound quite right when going by textbook definition.
At least one definition of “cyborg” includes computers with the capacity for humanlike thought. In which case C-3PO might himself be considered a cyborg.
It seems to me thatC-3PO is able to speak all “human” languages, while R2D2 is able to interface with all computer systems. As a combination, they offer some interesting potential as a story element.
I always figured since he was a protocal droid it was a PC term nobody ever used for droids.
Droid is to Cyborg as Janitor is to Sanitation Engineer.
Lobot (Lando’s majordomo on Cloud City…the one with the wraparound headphones) was an actual cyborg. So was Dengar, one of Vader’s bounty hunters*.
However, I’m pretty sure all the phrase means is human/machine relations…remember that 3PO said he could speak with not only binary droids, but the vaporators on the Lars farm.
*On the other hand, another one of the bounty hunters was an actual droid.
Despite being a translator C3PO rarely translates (he does with the Ewoks).
I always found it interesting (and liked it) in the Star Wars series that each race spoke its own language to others and everyone just seemed to understand. There are numerous times where another race is babbling unintelligbly to us but those in the movie all understand fine and respond in English which the “alien” (quotes because c’mon…everyone in the movie are aliens to each other) likewise gets just fine (e.g when Dooku is handed the plans for the Death Star he understands the languages around him just fine).
Hell, Luke seems to understand R2D2’s bleeps and bloops often enough. Although why the hell R2 couldn’t be given a voice synthesizer in that day and age is beyond me. R2 can reprogram the Death Star but can’t say two words? Bet there was a Radio Shack on the Death Star they could have nabbed one from.
I imagine it went something like this
Lucas,
Hmm, C-3PO, interpreter? no, public relations, hmm, human relations, human droid relations, human robot relations, hey how 'bout human cyborg relations.
Flunky 1
Ooh, cyborg relations, that’s cool.
Flunky 2
Well, technically, that isn’t the proper use of the term cyborg, besides wouldn’t ease of communication be something you’d design into a cyborg?
Lucas
Oh grow up!
Also for Jabba.
Luke had a translator built into his X-Wing. You can see words scrolling on it when R2 talks. Outside the X-Wing, I think he was generally interpreting R2’s tone, not literally translating into Basic. R2 was fairly expressive, after all.
You also have to remember that R2 and 3PO weren’t typical for droids, either. The SOP for droids was to regularly wipe their memories, thus ensuring that they didn’t start to establish a personality of their own. “Our” droids had somehow managed to escape that fate, and then they were firmly established as kind of “family” to the principals of the Rebellion, so they escaped it thereafter, as well.
Most droids didn’t have anywhere near the personality that R2 and 3PO did. That hinders communications.
Don’t forget General Grievous
He was taller than I expected.
R2D2, Gonk, FX7, etc aren’t exactly “android,” either. 
I think it’s similar to Lucas using “parsecs” as, apparently, a measure of time instead of distance (and, yes, I know, various tortured “explanations” of that have been created in the years since).
My suspicion is that, in both cases, Lucas wanted a cool-sounding word, and one that the viewer would recognize, but he wasn’t too worried about it being terribly accurate.
I think “cyborg” was used in the same way as was “parsec” which is to say, very very very loosely. Which is also to say, with a generous helping of fanwank. Yes, Luke and Vader are cyborgs in the conventional sense, but C-3PO is an android in the conventional sense.
Usually in ‘real life’ cyborg implies some amount of biological material in addition to mechanical/robotic. But Lucas probably meant it in the same sense that “android” is usually used, meaning “completely mechanical robot with some sort of humanistic aspect such as AI or body shape”.
Heh. C3-P0 just wanted something fancier to introduce himself with than “butler” or whatever. He probably considers himself a more refined white collar worker than most droids.