The reason behind the common 'achoo' sound made when sneezing has been revealed, much to the surprise of many.

The sound is an onomatopoeic representation of a sneeze, but it's not a natural response as one Reddit user pointed out.

They shared: "Today I learned that the 'achoo' sound is a learned cultural behaviour, not a biological reflex. This explains why people who are born deaf typically do not vocalize a sneeze, and why sneeze sounds vary significantly by country."

An article from Popular Science was also shared in the post, with this highlighting that the 'achoo' sound is specific to English speakers. Different cultures have their own versions, such as 'achoum' in France and 'hakashun' in Japan.

Partially deaf journalist Charlie Swinbourne, writing for The Limping Chicken, a blog for the deaf community, explained: "While deaf people sneeze naturally, hearing people feel compelled to add sound effects."

The revelation sparked a rush of comments on Reddit, with thousands sharing their thoughts. One user commented: "Learning to say 'achoo' (or equivalent) when sneezing and thinking it's just what sneezes sound like is the most human thing ever. We really are a bunch of goofy kids aren't we."

Another added: "Learned vocalisation with dialects makes sense. My household's sneezing sound is 'HHHHHHRESH' and it kind of freaks people out."

A third shared: "My mom practically screams when she sneezes it drives me crazy sometimes, she insists it's an uncontrollable reflex."