Usually, word-final „ę” is pronounced simply as „e”. Some people nasalise it slightly, but it's not required. Nasalising it too much is hypercorrect.
I've noticed the duo audio seems to really nasalize it when the next word starts with a consonant, like "piszę list". Is there anything to that? Or just the tts engine being hypercorrect?
Ja piszę, ty piszesz, on/ona/ono pisze, my piszemy, vy piszecie, oni/one piszą
So the only difference between I am writing, and she,he,it is writing is the accent on the letter e? Pisze vs Piszę. If you were to use the wrong one would it, in Polish be an obvious error?
In speaking there is almost no difference between "piszę" and "pisze". But in writing it's a major error. In Polish we often omit the subject like ja/on/ona (I/he/she) so that e/ę at the end of the word is the only one sign revealing the subject. Sorry for my English ;)
However, I don't think you would write pisze on its own, simply, once it doesn't give away who you are talking about (the subject). So, assuming you would need to mention the subject in case you talked about the 3rd person, I believe it would be known while writing even if you didn't write the letter correctly.
In other words, I mean, if you are talking about the 1st person, you'd either write it like "piszę" and incorrectly like "pisze", and people would still assume you're talking about the 1st person because you didnt make the subject clear!
Now, even incorrectly writing, if you were talking about the 3rd person, I tend to think you would specify the subject, and therefore, it would be still understandable.
On/Ona pisze or piszę.
But don't write it wrongly. It's better to avoid these situations by even specifying the subject, in case you're not sure of how to write it.
When pronouncing the two, they sound the same. Oftentimes, Polish speakers will understand whether you are saying "I am writing" or "He or she is writing." When written down, they make a huge difference. Hope this helps!
Every single day, I read a few comments claiming that a correct (even starred) answer was rejected. It seems impossible that all of those people made bigger typos, there clearly must be some bugs. Although I don't think I personally had any correct answer rejected in any course...