In Swedish we have ”Vilket/Vilken” which means WHICH. The reason is in Swedish 2 sorts of nouns: ETT or EN. Approx 10 % of nouns wtih ETT and most with EN. For exemple a tree = ett träd and a car = en bil.

The word WHiCH in Swedish is to the noun we talk about, If the noun with ett, we use VILKET and with en, we use VILKEN,

Vi har ett träd, vilket det finns i trädgården.’’
We have a tree, which is in the garden.

Vi har en röd bil, vilken den är för oss alla i familjen.
We have a red car, which is for all of us in the family.