Breakdown of Olenko tietoinen kaikesta, mitä ostan?
olla
to be
ostaa
to buy
kaikki
all, everything, everyone
mikä
which (relative pronoun)
Questions & Answers about Olenko tietoinen kaikesta, mitä ostan?
Why do we use mitä here instead of jota to mean "that"?
Normally, you use a form of joka to refer back to a specific noun. However, when referring back to an indefinite pronoun like kaikki (everything), you must use a form of mikä.
How does this connect to the se, mikä structure we're currently learning?
It uses the exact same rule! Just like the demonstrative pronoun se (it/that) pairs with mikä instead of joka in relative clauses, the indefinite pronoun kaikki (all/everything) does the exact same thing. If the sentence were "Am I aware of that which I buy?", the structure would be perfectly parallel: Olenko tietoinen siitä, mitä ostan?
Why is mitä in the partitive case, rather than the basic form mikä?
A relative pronoun always gets its case from its grammatical role in its own sub-clause. In the clause mitä ostan, the relative pronoun is the object of the verb ostan. Because "everything" is being treated as an indefinite mass of things you are buying, the object takes the partitive case.
Why is the word for "everything" in the elative case (kaikesta)?