In formal speech, it should almost always kept, but in colloquial speech it's fine to omit it.
vytah is correct. You can usually leave out the Czy at beginning of a question.
Apart from the question mark, how do you know it's a question? "you love this child" vs "do you love this child"?
Only the question marks shows it here.
Or you could just start with "Czy" to make it obvious that this is a question.
No, that's just plural. Polish doesn't use plural form of the verb as Formal You.
"kochać" takes Accusative, the neuter (as "dziecko" is neuter) Accusative form is "to".
"tego" is Genitive neuter or masculine.
Do we have to learn the verbs that take accusative and genetive or is there a question we can ask to find which case to use?
This new male baritone voice is more difficult to understand than the female.