Translation:Do you like to play the piano with your sister?
So, this time it tells me I need the article "the" in English, while in earlier similar sentences, it told me I had to have the article "a" or no article at all. Let's face it, Ukrainian is a language without articles, so both "the" and "a" should be at least grammatically acceptable in all situations.
The actual normal common meaning of this sentence is, "Do you like to play the piano with your sister?". We omit the pronoun that is the same as the subject (e.g. "Він ... з сестрою" would mean "He ... with his sister").
"With the sister" is the second most meaningful translation (e.g. the person has several sisters, one of them was mentioned earlier, so she's referred to as "the sister").
The weird translations would be: "with my sister" (nobody skips the pronoun like this, even when talking to parents, no idea if it used to be common before, but no, I wouldn't accept this translation) and "with a sister" (what is it supposed to mean even??)
It sounds strange to say in English, "to play the piano with the sister?" I don't know how you would write it in Ukranian, but to say either "to play the piano with sister" or to designate whose sister such as, "Do you like to play the piano with your sister?" both sound more natural to my ear.
"to play piano with sister" is grammatical?
"with the sister" could mean he has many sisters and one of them was mentioned earlier, and she is "the sister" in this sentence. I do agree that the most common and natural meaning is actually "with his sister". I don't know why the displayed one is "with the sister". I want to change it so that "the" is accepted, but the default is "his".