How does everyone in Star Wars understand droidspeak?

Question

All throughout the Star Wars movies, we see the droids emit several beeps and whirs, and the humans reply to the droid as if it were a normal conversation.

How can every character in Star Wars fluently understand droidspeak?

We know that Anakin Skywalker could speak several languages by the age of 9, including droidspeak. Is this language just something standardly taught to young children across the galaxy? Droidspeak is a complicated language. Are children in Star Wars born knowing it? Do they learn it like their own language, from their parents and surroundings?

(This question has been associated with "How do people understand astromech droids?". I am asking about all types of droids and their language droidspeak (or Binary), not specifically astromech droids, although the questions are fundamentally similar)

**edit: I have found evidence for this question in the show Star Wars Rebels (which is canon). In one scene, Zeb says to Ezra "Wait, you actually understand that glorified beeping garbage can?" (referring to a droid) and Ezra responds: "Yeah, sort of. I'm learning." which implies that droidspeak can be learned, but is not widely known. **

Answer 1

"Most people" don't speak droidspeak. Only those that work around droids bother to learn it, and even then inexpertly.

Notable characters who can understand droid (without a translator device) are;

Luke

“Artoo?” he asked, brightening, and a moment later the blue-and-white astromech rolled into view, chirping and whistling at length.

“Yes,” Luke said. Decades of missions with R2-D2 had left him reasonably fluent in droidspeak, but the astromech’s list of accusations was both lengthy and highly specific. “No, I—yeah, it’s true.”

R2-D2 squawked derisively.

“Hey, sacred island,” Luke said. “Watch the language.”

_{^{The Last Jedi: Official Novelisation}}

Rey

To most people, the beeping would have sounded like mechanical gibberish. But Rey was good with technology and had studied the communication patterns of droids. And that droid was especially eloquent—particularly in his choice of insults toward the Teedo.

_{^{The Force Awakens - Rey's Story}}

Poe

BB-8, secure in the astromech socket behind the cockpit of Poe’s X-wing, burbled a question. Plugged into the fighter, the droid’s binary-speak was automatically decoded and displayed on the console, but Poe didn’t actually need to read the translation to understand what the droid was asking.

_{^{Star Wars: Before the Awakening}}

Anakin

Answer 2

Most people do not understand Binary (the droid language). It is very clear, for example, that Luke does not understand R2-D2’s speech in The Empire Strikes Back.* There are a number of instances that make clear.

• When the droids congratulate Luke on his recovery from the Wampa incident, C-3PO first speaks for himself, “Master Luke, Sir, it’s so good to see you fully functional again,” then translates R2’s Binary utterance, “Artoo expresses his relief also.”

• Even more clearly, when Luke responds to something R2-D2 says when they on Dagobah, Luke makes it clear he does not actually know what his droid is saying: “If you’re saying coming here was a bad idea, I’m beginning to agree with you.”

*Luke can, however, understand R2-D2 when they are in his X-wing, with the ship’s computer translating R2’s messages into a written format, appearing on Luke’s video display.