I, living in Poland, am very used to writing the laughter sound as "hahaha". (It should be with spaces - at least in Polish - but... Ain't Nobody Got Time For That and apparently "cha cha cha" is also correct.)
Imagine my surprise, when we made some new Arabic speaking friends in Dubai (Hi Jihed!). They use "hhhh" which is another kind of funny for us.
I asked around and it turns out that in Spanish speaking folks use "ja ja ja" (Thanks Domi). Although it is logical, I did not expect that.
What other laughter notations do you know?
Cheers.