A new study has found that genes may actually contribute to learning the supposed "tonal languages", such as Chinese.
Dan Dediu and Robert Ladd of Edinburgh University, UK, have exposed the first obvious connection between language and genetic variation.
Slight pronunciation differences in tonal languages can fundamentally alter the meaning of words, which may be one of the reasons why these languages are so tough to learn for speakers of non-tonal languages such as English.
By means of statistical study, the pair demonstrated that people in regions where non-tonal languages are spoken are more expected to bear diverse, more freshly evolved forms of two brain development genes, ASPM and Microcephalin, as compared to people in tonal regions.
"The results open up a whole new field of inquiry that links language evolution with adaptive molecular evolution and brain function," Newscientist.com quoted Bernard Crespi, an evolutionary biologist at Simon Fraser University in Burnaby, Canada, as saying.
Given that both genes function in brain development, Dediu and Ladd recommend that they may have restrained effects on the administration of the cerebral cortex, as well as the areas that develop language.
According to Ladd, brain anatomy varies between English speakers, who are excellent at learning tonal languages, and those who find it difficult.
Ladd now wants to determine whether parallel differences can be found between individual carriers of the ASPM and Microcephalin variants.
An enduring mystery is about the role of natural selection. It has been debated that the newer variants of these two genes are positively selected, but until now nobody has been able to explain how they might offer a selective advantage.
Dediu and Ladd do not believe that the genes' association with tonality could be the answer to this puzzle.
"There is absolutely no reason to think that non-tonal languages are in any way more fit for purpose than tonal languages. Chinese society developed advanced technology, politics and philosophy with a tonal language just as successfully as roughly contemporary eastern Mediterranean societies with non-tonal languages," Ladd said.
However, Crespi considered that the lesser intricacy of non-tonal languages could present a selective advantage.
"Adoption of a simpler language might be 'easier', allowing for faster acquisition of language or other brain functions in early childhood. These ideas could be tested," Crespi said.