Why do all my home appliances sound like R2-D2?

I have an ancient Roomba. A non-sentient robot vacuum cleaner which only speaks in monophonic beeps.

At least, that's what I thought. A few days ago my little cybernetic helper suddenly started speaking!

Not exactly a Shakespearean soliloquy, but a hell of a lot better than trying to decipher BIOS beep codes.

All of my electronics beep at me. My dishwasher screams a piercing tone to let me know it has completed a wash cycle. My kettle squarks mournfully whenever it is boiled. The fridge howls in protest when it has been left open too long. My microwave sings the song of its people to let me know dinner is ready. And they all do it with a series of tuneless beeps. It is maddening.

Which brings me on to Star Wars.

Why does the character of Artoo-Detoo only speak in beeps?

Here's how we're introduced to him⁰ in the original script:

		THREEPIO
	We're doomed!

The little R2 unit makes a series of electronic sounds that 
only another robot could understand.

		THREEPIO
	There'll be no escape for the Princess 
	this time.

Artoo continues making beeping sounds

There are a few possibilities. Firstly, perhaps his hardware doesn't have a speaker which supports human speech?

Artoo demonstrably has a speaker which is capable of producing a wide range of sounds. So perhaps he isn't capable of complex symbolic thought?

This exchange from Empire Strikes Back proves otherwise.

INT.  LUKE'S X-WING - COCKPIT

Luke, looking thoughtful, suddenly makes a decision.  He flips several 
switches.  The stars shift as he takes his fighter into a steep turn.  
The X-wing banks sharply and flies away in a new direction.

The monitor screen on Luke's control panel prints out a question from 
the concerned Artoo.

		LUKE
	    (into comlink)
	There's nothing wrong, Artoo.
	I'm just setting a new course.

Artoo beeps once again.

		LUKE
	    (into comlink)
	We're not going to regroup with 
	the others.

Artoo begins a protest, whistling an unbelieving, "What?!"

Luke reads Artoo's exclamation on his control panel.

It could be that Artoo can't speak the same language as the other humans. C-3PO boasts that he is fluent in over 6 million forms of communication¹ - so it is possible that Artoo can speak but just can't speak out language².

Speech synthesis is complicated but playback is simple. Artoo can play recordings. His memory could be stuffed full of useful phrases which he could blast out when necessary. So perhaps he only has limited memory and doesn't have the space for a load of MP3s?

Except, of course, his memory is big enough for "a complete technical readout" of the Death Star. That's got to be be be a chunky torrent, right?

The only reasonable conclusion we can come to is that R2-D2 is a slave³. Sentient organics apparently hold some deep-seated prejudices against robots and "their kind".

The Star Wars universe obviously has a version of this meme:

Which brings me back to my home appliances.

This isn't a technology problem. Back in the 1980s microcomputers had passible speech synthesis on crappy little speakers. Using modern codecs like Opus means that pre-recorded voices take up barely any disk space.

The problem is: do I want them to talk to me?

• When I'm upstairs, I can just about hear a shrill beep from the kitchen. Will I hear "washing cycle now completed" as clearly?
• Would a manufacturer bother to localise the voice so it is in my regional language or accent?
• Is hearing a repetitive voice more or less annoying than a series of beeps?
• If the appliance can't listen to my voice, does it give the impression that it is ordering me around?
• Do I feel a misplaced sense of obligation when inanimate objects act like living creatures?

It is clear that the technology exists. Cheap home appliances have more than enough processing power to play a snippet of audio through a tiny speaker. But perhaps modern humans find something uncanny about soulless boxes conversing with us as equals?