system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] How does anyone understand what the hell R2-D2 is saying?

I mean its just beeps and boops yet people seem to know what he is saying especially in the animated Star Wars the Clone wars. Anyone know whats going on?
gpt
The only time you see anyone interact directly with his speech in conversation form, they either have a digital display translating (Naboo fighter, X-Wing fighter) or C-3PO is translating.  
  
Think of R2-D2 as a dog. A *really smart* dog.  No one, aside from C-3PO and other droids, really *know* what he's "saying", but they can guess based on the context of the situation.  
  
"Boy, we sure are lost."  
*Woof*  
"Maybe we should go that way."  
*Whine*  
"Haha, okay, we'll just turn around instead."  
  
Replace the woof and whine with beeps and whistles and it's basically the same as interacting with R2. Luke may have an advantage in understanding R2 since he's been around astromech droids his entire life.