Learn Turkish: Müşterinin teklifi reddetmesi beklenmedik bir karar. - The customer's rejecting the offer is an unexpected decision.

This sentence uses an action/event clause as its subject. In these clauses, the 'doer' of the action takes the genitive case (like 'the customer's'), and the action itself is turned into a verbal noun with a possessive suffix (reddetmesi). Together, they form 'the customer's rejecting.'

Why does teklif (offer) take the accusative case (teklifi)?

Even though reddetmesi acts like a noun in the main sentence, it still behaves like a verb inside its own mini-clause. Because 'the offer' is the specific thing being rejected, it takes the accusative case as the direct object of the verbal noun.

Can you break down the word reddetmesi? Why are there two 'd's?

It comes from the noun ret (rejection) and the helper verb etmek (to do/make). When they combine, the 't' changes to 'd' and doubles, forming reddetmek. We then add the short verbal noun suffix -me, followed by the 3rd person possessive suffix -si to link it back to müşterinin.

How does the word beklenmedik (unexpected) get its meaning?