Does matter accelerate to the speed of light as it approaches the singularity?
There is indeed a sense that infalling objects accelerate to the speed of light as it reaches the event horizon, but you need to be careful what you mean by the speed of the object because the speed is observer dependent.

This is explained in detail on the Physics site in my answer to Will an object always fall at an infinite speed in a black hole? An observer watching from far from the black hole would see the falling object initially accelerate towards the black hole but then decelerate to a halt at the event horizon. However an observer hovering a distance $d$ above the event horizon would see the falling object pass them at a speed:

$$ v = c \sqrt{\frac{r_s}{r_s + d}} \tag{1} $$

where $r_s$ is the radius of the event horizon. As the distance above the horizon $d$ goes to zero the speed calculated from equation (1) goes to the speed of light $c$.