roughen

Red whirls on this rabbit’s tongue are filiform papillae, which roughen the tongue and help move food around the mouth.

Mark was the timid new kid then, which Darren, roughened up from life with an abusive father, exploited in their game of chicken.

The general idea is that ground surfaces roughen after the mass movement of rocks and soil, so that landslide deposits are the roughest right after the landslide occurs and become smoother over time.

Auto-tune aside, fans will notice that Thorn's voice has deepened and roughened.

Though it may seem counterintuitive, roughening a ball’s surface delays the separation of the boundary layer and keeps a ball in turbulent flow longer.