For the most part, the thousands of languages in the
world today fall into one of two categories: tonal or nontonal.
Two linguists believe they know the genetic underpinnings
for these differences. During a study of linguistic and
genetic data from 49 distinctive populations, the authors discovered
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a struck correlation between two genes involved in
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brain development and language tonality. Populations who
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speak nontonal languages have newer versions of the genes,
with mutations that began to appear roughly 37 thousand
years before. "You can consider this as the first of the many
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possible studies that we could do to try to find a genetic
basis for language and language typology and the different
populations that speak a language," says Patrick Wong, the
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assistant professor at Northwestern University, who was not
involved in this study. In English, the pitch which a word
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is spoken convey emotion but usually does not affect its
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meaning. But in many languages tone changes the meaning
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of words. For instance, the Chinese word huar said in a high
pitch means flower, but in a dipping pitch meaning picture.
The new research ties this difference to those two genes.
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The exact functions of both genes are still open to debate, so
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they are known to affect brain size during embryonic development.
They presumably have something to do with brain
structure, because there are mutations of the genes that lead
to microcephaly, a condition in which a person"s brain is
much smaller than the average size for his or her age.