If you say “ma” in Mandarin, you could be saying mother, hemp, horse or scold, depending purely on your pitch.
This so-called lexical tone is used in around half the world’s languages, including Thai and Cantonese, yet tones are meaningless in other languages such as English.
A new study, published in the journal Science Advances, suggests that subtle genetic differences play a role in how these language differences evolve.
More than 7000 languages are spoken around the world, with a diverse range of features including click consonants, whistling, variable word order and use of sound to convey meaning. Yet, little is known about what drives these differences.
Population studies have suggested genetic diversity could shape language; for instance, people in countries of sub-Saharan Africa and East and Southeast Asia with tone languages are more likely to have certain genes, but as yet there has been no direct evidence.
To investigate the role of gene expression in pitch perception ability, Patrick Wong, from the Chinese University of Hong Kong, and colleagues recruited 400 adult native Cantonese speakers aged 18 to 27.
The volunteers performed a range of tasks related to lexical tone, rhythm and pitch in music and general cognition, to control for musical backgrounds and education, and provided saliva samples for genetic testing.
Results showed that around 70% of participants had a pair of T alleles representing the “TT” genotype of the ASPM gene, which was previously found to be more prevalent in countries with tone languages
It has also been associated with the auditory cortex, and individuals with the gene had higher tone perception ability.
Those with a different genotype were less proficient with Cantonese tones, but not with other aspects of language or cognitive functions, confirming that the identified genotype is likely associated with tonal ability.
The researchers note that other genes are likely to be involved, but the study opens doors to explore further genetic underpinnings of language evolution.
The finding could have clinical applications; for instance, tone perception is a key marker for communication disorders in Chinese speakers.
Intriguingly, previous research by Wong’s team found that tone perception was strongly associated with musical training, and in the present study, musical ability did improve tonal ability in individuals without the ASPM genotype.
This aligns with other work by the group that found native English-speaking adults with a musical background were better at learning a tone language.
So, if you do want to visit Asia, musical training might help avoid embarrassing mispronunciations.
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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