The "Beep-Boop" noises that are often associated with robots in movies (like R2D2). Do they have an origin? Robots haven't existed for long so I imagine someone started it recently.
Are they from an old movie that set the standard? From a book? Or were early robots actually making those noises?
If you go back to much older robots in movies and TV shows, there really isn't so much beeping as whirring. The classic Robbie the Robot was a prime example of this, with a large glass head that you could see the whirring mechanical parts, as well as lights flashing on him. The beeping was relatively common as well.
This is because this is how classic mechanical computers worked. They had moving parts, which were noisy as hell, lots of flickering lights, and included speakers for beeps and bloops which indicated the statuses of various parts. When it came time to imagine a robot, well, it was a computer with legs. You'll hear the same thing often when a room full of computers (or in that era, a room full of A computer) is shown: whirring and beeping and flashing lights.
R2D2 very clearly drew inspiration from this idea, and took the idea of the beeps which represented statuses and allowed them the complexity to be a language.
This is by no means universal, but the noises tend to be associated with robots who are clearly robotic. More anthro-centric robots (Terminator, Gort) do not have these associated sounds and such. It is a subtle way to let the observer know that this robot is more man-like. Terminator, for example, noticeably begins to whir and whine as the flesh is removed from the metal endoskeleton in both Terminator 1 and in Terminator 2 (particularly after his arm has been removed). If we look at Lost In Space (which Robbie also occasionally starred in) the main Robot character was more anthropomorphised, with arms, a head, and even a voice. You didn't tend to hear it except when he was "computing" but there was subdued whirring noises and such.
In short, it's a long history that tends to add flavor to the idea that this creature is a robot. But if you are looking for the first time a robot was on the screen and made a beeping noise, that I couldn't say.
It's actually wrong to say that Star Wars followed in the footsteps of preceding movies.
Droidspeak, a.k.a. Binary, was in fact an original invention for Star Wars, the result of using an analogue synthesizer and mixing it with Ben Burtt's own voice. This was a deliberate move on the part of George Lucas, who wanted to differentiate Star Wars from Sci-Fi films of the preceding decades, much of whose sound effects were distinctly electronic, and who made Burtt go through several iterations until he came up with a sound for R2-D2 that was "organic" enough.
The fad of having electronic soundtracks for Sci-Fi movies has as its archetype Forbidden Planet, of course; although as noted Robby itself clatters mechanically.
It perhaps seems that there is a correlation simply because of fashion. Robby was very popular, and appeared in a lot of films and television programmes, so it may seem that that era depicted robots in "Robby-like" fashion simply because of the ubiquity of Robby itself.
Similarly, Ben Burtt spent 28 years at LucasFilm, and did a lot of sound design and editing, including famously two of the robots in WALL-E. So a lot of sound design may be seen to be "Burtt-like" simply because he did it. And of course, R2-D2 was an inspiration it its turn to others, just as it was inspired by Huey, Louie, and Dewey in Silent Running.
They, of course, were mute; and the simple truth is that there is no single characteristic "robot sound" in the history of Sci-Fi cinema, and no single origin for the many that there are. There are a lot of sounds: the mutes like Gort from The Day The Earth Stood Still, the mechanical noised, the human voices processed beyond recognition (Vincent in The Black Hole was a voice-controlled Korg synthesizer, and designed to sound like a servo-motor operating), the electronically synthesized, the human voices processed but still comprehensible like RoboCop, other things electronically processed (the voice of Max in The Black Hole was the sound of a growling panther run through a Vocoder, for example), plain old human voices (such as Robin Williams in Bicentennial Man), and so on.
Interestingly, there are, here and there, real robots, outwith fiction, whose design has been influenced by Sci-Fi robots; and in fact far from fictional robots being based upon real sounds (rather than, as is far more prosaically the case, whatever the sounds effects people could come up with and decided fit the film, from vocoded panthers to a Disney workshop bandsaw breaking) in some respects real robots have been modelled on the fictional ones. The designers of MIT's RoCo, for example, explicitly imitated the sound style of R2-D2.
Tl;dr
The cars must have wheels, airplanes have to have propellers or jets, flying cabs have to be Chevy Impala-shaped otherwise audience would have problems to identify such objects as cars, planes and cabs. Computers had to beep and flash lights because computers did beep and flash a lot.
The very first robots were artificial people actually. See the play R.U.R. by Karel Capek.
Much later the actual technology brought (industrial) robots (mechanical manipulators) to reality and writers accomodate it. Such robots are driven by (high power) electromotors, pneumatic drives or hydraulic drives. These were not as "silent" as they are nowadays. See Marvin, the paranoid android, from The Hitchhiker's guide to the Galaxy.
The old computers had very few outputs: Screen (terminal), printer (dot matrix), buzzer and notification lights. Even in 90's the personal computers were quite noisy with "bee-boop" signals and flashing/glowing LEDs to warn/notify the user and noisy hard/floppy drives. The production of sound (music) needed special resources and voice synthesizers were unique and needed much more computational resources.
The robots and androids were supposed to do such noises, othewise it would be "just people in clumsy boxes". Such robots were to be results of mechanical engineering, therefore build of motors and computers. And computers were doing "bee-boop" noises.
The noise produced by the robot and the "beep-to-words" ratio signals the audience how far in the future the plot is set. The further future and the more advanced technology means the fewer beeping noises.
The R2D2 is "very simple" and verstile robot. It is just moving computer and its computational power is the thing designer focused on at first. There was not enough room for voice syntesizer and reproductor, right? Simple beeper, printer and holographic projector is much tougher and more compact solution.
The T3PO, on the other hand, is very clumsy andriod designed for one purpose only - translating from one language to another. Therefore the voice syntesizer as the only output and no beeper.
Sonny, from I, Robot, is much advanced android and you can only hear his motors work. He can speak, so there is no need for him to beep.
The noises derive from analog encoding of digital information as used on early computers. You can hear it in the typical 'modem noises' familiar from the dial-up internet days, but similar techniques were used on tape drives as well.
The R2D2 beeping sounds date to the mid 1970's, when the best a computer could do as regards sounds were single monotones. It wasn't until around 1980 that the polyphonic (more than one note simultaneously) synthesizer became available. So R2D2's beeping was likely an attempt to use a computer/robot sound cue that was familiar to 1976 viewers, although the sounds made do tend to follow human emotions: excitement, annoyance.
Note also that the non humanoid robot didn't speak in a human fashion, while the humanoid form robot did.
The idea of humanizing a non humanoid robot traces back to a 1972 film, Silent Running, with the three robots Huey, Dewey, and Louie. One of the more endearing aspects of that film was how those robots, even though they made no sounds, and did not look even remotely human, convincingly (and unexpectedly) exhibited human characteristics... like cheating at cards. When one of them got clobbered accidentally by Bruce Dern in the 4 wheeler, you really did feel bad.
How is R2D2 related to Silent Running? The director of that film, Douglas Trumbull, was the special effects director on Star Wars IV. Much like the Silent Running robots, R2D2 became almost human by it's actions and gestures, not spoken words.
