Questions & Answers about Pokażę dziecku ten nowy sklep.
Why is it dziecku instead of dziecko?
Dziecku is in the dative case. We use the dative case for the indirect object, which answers the question 'to whom?'. Since you are showing the shop to the child, the neuter noun dziecko changes its ending to -u to become dziecku.
I thought the direct object of a sentence takes the accusative case. Why doesn't sklep change?
It actually is in the accusative case! Sklep is a masculine inanimate noun (a non-living thing). For masculine inanimate nouns, the accusative case looks exactly the same as the basic dictionary form.
Why do ten and nowy also look like their basic dictionary forms?
Adjectives and pronouns must match the noun they describe. Because sklep is taking the masculine inanimate accusative form, ten and nowy do the same. For masculine inanimate objects, this form is identical to their basic nominative form.
Why does pokażę mean 'I will show' instead of 'I am showing'? There is no future helper word like będę.
The verb pokazać is perfective, meaning it describes a completed action. In Polish, when you put a perfective verb into what looks like the present tense conjugation, it automatically creates the future tense. So pokażę translates to 'I will show'.