Question: Obviously, Han understands Chewbacca (almost) perfectly. In the prequel trilogy, Yoda seems to understand him too. In at least one scene in the original trilogy, C-3PO also understands Chewie, which is logical, since - as a protocol droid - translation is one of 3PO's primary functions.

> 
> THREEPIO: Captain Solo, this time you have 
>  gone too far. 
> 
> 
> (Chewie growls) 
> 
> 
> THREEPIO: No, I will not be quiet, Chewbacca. 
>  Why doesn't anyone listen to me?
> 
> 
> 

Does anyone else in the *Star Wars* movies understand Chewbacca?
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Answer: 
Obi-Wan Kenobi both speaks and understands Shyriiwook.
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From the [script](http://www.imsdb.com/scripts/Star-Wars-A-New-Hope.html) for *A New Hope*:

> 
> Ben is standing next to Chewbacca, an eight-foot-tall savage-looking creature [...] He is a two-hundred-year-old Wookiee and a sight to behold.
> 
> 
> Ben speaks to the Wookiee, pointing to Luke several times during his conversation and the huge creature suddenly lets out a horrifying laugh. Luke is more than a little bit disconcerted and pretends not to hear the conversation between Ben and the giant Wookiee.
> 
> 
> 

From the [novel](https://books.google.co.uk/books?id=HNBjb2dkVFUC&q=ben+talking+to+the+wookie+in+its+own+language&dq=ben+talking+to+the+wookie+in+its+own+language&hl=en&sa=X&ved=0CDAQ6AEwAmoVChMIw_yvs_PsyAIVBWsUCh3uTgeq):

> 
> All but old Ben - Ben, who was talking to the Wookiee in its own language, quarreling and hooting softly like a native.
> 
> 
> 

In *The Force Awakens*, Rey also understands it.
------------------------------------------------

As shown in [this answer from @phantom42 on another site](https://movies.stackexchange.com/a/45185/27759), Rey has at least some understanding of Shyriiwook. Quoting from the novelisation of *The Force Awakens*:

> 
> She tried to find something to say to that, something worthy of the sentiment and the risk they had undertaken. She failed miserably. Chewie, however, had something of his own to add. Whatever the Wookiee had uttered caused tears to well up in her eyes. Having never found himself in such a position before, Finn was unsure how to respond. Knowing well her inner toughness, he wondered what Chewbacca had said that could have inspired such a reaction.
> 
> 
> “What’d he say?”
> 
> 
> She sniffed and wiped at her face. “That it was your idea.”
> 
> 
> 

---

Less canonically, **[Sabine Wren](http://starwars.wikia.com/wiki/Sabine_Wren)** also speaks [Shyriiwook](http://starwars.wikia.com/wiki/Shyriiwook/Canon) (so presumably understands it too).

> 
> "...it's rough on my throat, I lost my voice for a day after bugging Zeb by serenading him in Shyriiwook."  
> 
> -- Sabine Wren, *Star Wars Rebels: Sabine, My Rebel Sketchbook*
> 
> 
>
**Understand Shyriiwook, Master Yoda does**
-------------------------------------------

> 
> When he told them the problem, **the Wookiees nodded and barked at each
> other so fast that it was difficult even for him to follow the
> conversation.** Then they turned and offered him one of their escape
> pods. Yoda accepted at once. The only problem left was how to get past
> the clone troops to the pod.
> 
> 
> [Revenge of the Sith - Official Novelisation](http://starwars.wikia.com/wiki/Star_Wars_Episode_III:_Revenge_of_the_Sith_(novel))
> 
> 
> 

As does Leia (although not as well as her official profile suggests)
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> 
> *“According to her diplomatic profile, Princess Leia speaks both
> Huttese and Shyriiwook fluently. **Regretfully, and as Your Majesty is
> keenly aware, the princess is merely proficient in Shyriiwook.** This
> is, naturally, a failure of mine and not the princess, but I worry
> that such an error might cause her embarrassment. Oh, it is too, too
> humiliating.”*
> 
> 
> [From a Certain Point of View](http://starwars.wikia.com/wiki/From_a_Certain_Point_of_View) - [Eclipse](http://starwars.wikia.com/wiki/Eclipse_(short_story))
> 
> 
> 

---

Lower canon films
-----------------

If we also include the [Star Wars Holiday Special](http://starwars.wikia.com/wiki/The_Star_Wars_Holiday_Special), then we can also add

**Chewie's wife Malla**, **his son Lumpy** and **his father Itchy** as well as **human trader [Saun Dann](http://starwars.wikia.com/wiki/Saun_Dann)**, all of whom demonstrate an ability to understand Chewbacca.