Obligatory xkcd: https://xkcd.com/638/
But that's a very superficial understanding of a language. Maybe we have different concepts of what understanding a language means.
Dogs are smart enough to grasp relatively advanced concepts, do you think you would understand the response if you asked "do you want food A, B, C, or D"? And I'm not talking about body language (them pointing at the thing) or training them to react in a specific way because that's actually you teaching them a language. Another example: listen to 2 dogs barking at each other. To what level can you understand what they are "saying"? Yes, you can say "aggressive" or "submissive". But is it fair to call that understanding the language? There has to be more to their language than just basic emotions.
Take this list of languages  (or any language that is completely foreign to you). If someone is speaking one of them to you and you can only guess things from body language or tone is it fair to say you understand that language?
The meaning of a lot of human languages or alphabets is completely lost even if they were conceived by humans almost identical to us biologically. Hoping to understand alien languages without the aliens helping us is a pipe dream.
There has been limited success with parts of Voynich Manuscript (some plants names?) and some interesting developments with rongorongo, but overall, yes, super hard. Hopeflly, Natural Language Processing might help, some promising results were reported for Linear B.
We understand natural constructs because we kind of understand the natural laws that govern them. We're nowhere near understanding the laws that govern the intelligent, conscious mind. Even our own.
P.S. Good luck with your project. Sounds very interesting and right on the money for this conversation.