|Laughter is easily recognized.|
The hearing people were able to identify some sounds, like laughing and sighing in amusement and relief, but certain sounds were harder. The sounds they could not identify were sounds of triumph.
The link above includes a recording during which you can hear the sounds as they were recorded. I'll warn you though... the recording is a bit difficult to hear. That guy talks fast! Still, it's very interesting.
The scientists are considering the idea that some nonverbal vocal communication is instinctual while others have to be learned. What do you think?