Speak harshly, maybe heatedly (5)

I believe the answer is:

grate

I'm a little stuck... Click here to teach me more about this clue!

'speak' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for grate that I've seen before include "Grind, rasp" , "Reduce to small shreds" , "Grind (cheese)" , "Grind (teeth)" , "irritating" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app