Questions & Answers about Wij hebben de aap horen gillen.
Why does this sentence use horen instead of the past participle gehoord?
Because of a special Dutch rule called the "double infinitive". When a verb of perception like horen (to hear) is combined with another verb, in this case gillen (to scream), it does not change into a past participle in the perfect tense. Instead, both verbs stay in their full infinitive form at the end of the sentence.
Is the word horen here matching the plural wij, or is it an infinitive?
It is an infinitive! Even though horen looks exactly the same as the present tense plural form for wij, it is actually the infinitive form here. The verb that is conjugated to match wij is the helping verb hebben.
Why are the verbs horen and gillen placed at the very end of the sentence?
In the Dutch perfect tense, the conjugated helping verb (hebben) takes the second position in the sentence, while the action verbs get pushed all the way to the end. When you have a double infinitive like horen gillen, they stick together at the very end, with the perception verb (horen) coming right before the main action verb (gillen).
The English translation uses the simple past ("We heard"). Why does Dutch use the present perfect (hebben ... horen)?
Dutch speakers use the present perfect tense much more often than English speakers do in everyday spoken language. While you could use the simple past (Wij hoorden de aap gillen), using the present perfect is very natural and common in Dutch for a completed past event.