"Are you mad?!"
How to do it: index finger pressed repeatedly to the side of the forehead.
Read our full phrasebook here Photograph: Guardian
Dividing up a sentence - firstly, secondly ...
How to do it: one flat hand, other one hits it in a "cutting" motion.
Read our full phrasebook here Photograph: Guardian
Explaining something
How to do it: hands in a rolling movement.
Read our full phrasebook here Photograph: Guardian
"I don't know/I can't help"
How to do it: hands open (palm upwards) at sides of body (chest level).
Read our full phrasebook here Photograph: Guardian