"You hear this man."
Translation:Ty słyszysz tego mężczyznę.
"słyszeć" takes Accusative. In Accusative, it is important whether a masculine noun is animate or inanimate.
For an animate masculine noun, and a man is obviously animate, the noun phrase (this man) takes a form identical to Genitive: "tego mężczyznę".
For inanimate masculine nouns, it is identical to Nominative: "Słyszysz ten telewizor" (You hear this television set).