Learn Dutch: Je moet de kattenbak nu schoonmaken. - You must clean the litter box now.

This is a compound noun made from kat (cat) and bak (box or tray). In Dutch, when the first noun only has a plural form ending in -en (like katten), we usually use the linking letters -en- to connect it to the second noun.

Why is kattenbak spelled with a double t, when the word kat only has one?

This follows the short vowel spelling rule. The a in kat is a short vowel. When we add the linking -en-, we have to double the t to keep the a sounding short. If we wrote katenbak, the a would be pronounced incorrectly as a long vowel.

I learned that schoonmaken (to clean) is a separable verb. Why isn't it split up here?

Separable verbs only split when they act as the conjugated main verb of the sentence. Here, the modal verb moet (must) takes that role in the second position. Because of the modal verb, the action verb (schoonmaken) is pushed to the very end of the sentence and stays together as a full infinitive.

What happens to the word order if I want to emphasize nu (now) by starting the sentence with it?