When my kids were little I used to remark how I thought their voices and laughter sounded like music. As people get older, I think this goes away somewhat and laughter and speech become more regimented, or predictable, somehow.
Anyway, about a century ago somebody analyzed this and came up with these interesting ideas:
It is a well known and easily demonstrated scientific fact that different people sound different vowels when laughing, from which fact a close observer has drawn the following conclusions: People who laugh in A (pronounced as ah) are frank, honest, and fond of noise and excitement, though they are often of a versatile and fickle disposition. Laughter in E (pronounced as ay) is peculiar to phlegmatic and melancholy persons. Those who laugh in I (pronounced as ee) are children or simple-minded, obliging, affectionate, timid, and undecided people. To laugh in O indicates generosity and daring. Avoid if possible all those who laugh in U, as they are wholly devoid of principle. ~ Henry Williams, A Book of Curious Facts, 1903
I don’t now how true it is but it would be fun to test it out.