Where does the 'i' come from in 'konia'? Does ń always change to 'ni' when an 'a' is added?
Polish spelling of ć, dź, ś, ź, ń sounds varies depending on context:
word-finally and before consonants trhey're spelt ć, dź, ś, ź, ń
before i they're spelt c, dz, s, z, n
before other vowels they're spelt ci, dzi, si, zi, ni
Ah, I see! I was aware that these various combinations had the same sounds, but I didn't realise there was such a simple rule. Thank you!
To add to this, the sound they all have in common is called Palatalization (when your tongue is raised up and as close as possible to your teeth), and it's a major defining feature of Slavic languages. It's also what makes them sound different from cz, ż, sz, rz, and n, which are "normal" and not palatalized. Ś/SZ are the most obviously different - like "Shh!" vs. the first S in "Sure", with an English accent.
One of the tricky things about Russian is that, a lot of the time, you have to memorize all kinds of rules for whether or not a consonant is palatalized. Polish literally spells it out for you 100% of the time!
Are there different Polish translations for "Can you hear this horse?" and "Do you hear this horse?"
Or can this Polish sentence mean both?
Generally "can you hear" often just means "do you hear", so both are accepted.
But if you literally mean "are you able to hear", that's "czy możesz usłyszeć" or even "czy jesteś w stanie usłyszeć"
What is the difference between Słyszysz tego konia? i Słyszysz ten kłoń? Besides it being a different case?
There is no such word as "kłoń" in Polish. I think what you meant to write was "Słyszysz ten koń?" but this isn't correct either because it's the wrong case. The only valid option is "Słyszysz tego konia?"
Why is it not slyszycie? Is it because it's a question and the second-person has two forms depending on if it's a question?