Learn Dutch: Heb jij de aap het kostuum laten dragen? - Did you let the monkey wear the costume?

This is the special double infinitive rule you are learning in this lesson. When you use the perfect tense with a causative verb like laten alongside another verb like dragen, laten does not turn into its past participle gelaten. Instead, it stays in its full infinitive form, leaving you with two infinitives grouped together at the end.

Why are both laten and dragen at the very end of the sentence?

In Dutch yes/no questions, the conjugated helping verb Heb goes at the very beginning. All the other verbs in the sentence are pushed to the very end. When you have a double infinitive like laten dragen, they sit right next to each other at the end of the clause.

Does laten mean to let or to make here?

It can mean either! The Dutch verb laten is used both for giving permission (to let) and for causing someone or something to perform an action (to make). Depending on the context, this could also perfectly translate to: Did you make the monkey wear the costume?

Why does de aap come before het kostuum in the sentence?

The word order shows us who is doing what. In a sentence where you let someone do something, the person or animal performing the action (de aap) comes before the object they are interacting with (het kostuum). If you swapped them, it would mean you let the costume wear the monkey!