That's starting to get into paralinguistic territory. Sneeze sounds, for example, are learned to a degree (think some people sneezing very quietly or very loudly), and can be relearned even though they are involuntary in their timing, unlike "real" words.
The physical sound of "haha" might be the same everywhere (to some degree, people laugh differently obviously) but different languages write "haha" different. Spanish: "jaja" or "jeje", Japanese: "wwwww"