The Dutch Grammar Forum

https://en.wiktionary.org/wiki/hebben#Verb
On this wiktionary page, in the 3rd meaning of hebben as a verb, there's an example sentence:

"Ik heb hem horen praten. ― I have heard him speak."

But right there it also wrote that "(auxiliary) Used to form the perfect tense of the active voice of most verbs, together with a past participle."

So there seems to be a contradiction: the past participle of horen is gehoord, so shouldn't we say instead:
"Ik heb hem gehoord praten."?

Thank you.

Indeed, the past participle of 'horen' is 'gehoord'. However, when the past participle serves as an auxiliary verb for another verb, we use an infinitive ('horen').

So instead of "Ik heb hem gehoord praten", we say "Ik heb hem horen praten".

See also: https://www.dutchgrammar.com/en/?n=Verbs.Au05