It's kinda like a semi casual sentence if you use yo form and in casual you use these kinds of sentence a kot where you cute the words short it is difficult to learn in starting but you get the hang of it soon
Welp, basically ga is added as a subject marker after a vowel. This is when something specific is being said. Like the cat is an animal. Sorry if im wrong, this is just me pouring all the current knowledge I have out.
That's not necessarily bad English, but the meaning is slightly different. In your sentence, the phrase "at the park" modifies "The singer" rather than modifying "sings," so I think that would be a different sentence in Korean.
You can download an korean keyboard from your settings! Well, depend on what kind of phone you got, but it'll allow you to flip through the two languages by using the space bar button (you'll see what I mean)
My translation is better. It is more likely that a person in conversation will be reporting a current event or an immediate future event, such as a scheduled one, than a recurring event, which is what the simple present describes in English.