If you get tongue-tied when trying to learn a new language, your genes may be to blame, a new study suggests.

While there is no gene yet found that is responsible for preprogramming a person with a given language, there does appear to be a link between types of two genes and the languages people speak.

The new findings could be the first sign of a subtle effect in which people's DNA could bias them toward learning a particular set of languages.

Robert Ladd and Dan Dediu at the University of Edinburgh in Scotland noticed the possible link while studying the genes dubbed Microcephalin and ASPM.

These genes play a role in brain development and appear to still be evolving in humans.

"I looked at maps of the distributions of the old and new versions of the genes," Ladd said. "And I said, that looks like the distribution of tonal languages."

In tonal languages, the same word can have widely different meanings depending on the inflection of the speaker.

The researchers scoured records of genes from societies around the world and compared their findings with the languages those groups speak.

While they didn't prove there's a direct link, they did reveal a strong connection between the versions of the two genes that people had and whether their native language was tonal or nontonal.

The results appear in this week's issue of the Proceedings of the National Academy of Sciences.

What Did You Call Me?

About half of all existing languages are tonal.

In Mandarin Chinese, for example, the syllable "ma" can take on several unique meanings.

When it's pronounced with a single high-pitched tone, "ma" means "mother."

But when it has a low-pitched lilt in the middle, it means "horse" - making it a word you don't want to mispronounce.

The other half of all languages are nontonal, meaning they use pitch only for things like marking a question.

If your ancestors were from Southeast Asia or sub-Saharan Africa, where the native languages are nearly all tonal, you probably have the older versions of both genes.

If your ancestors were all from Europe, where people mostly speak nontonal languages, you probably have the new version of Microcephalin and have a 50-50 chance of carrying the new ASPM gene.

These genes may give you a bit of a tin ear for tone, the study suggests.

Evolving Tongues

The effects of these genetic markers might not be obvious in babies learning their native tongues.

As far as anyone has been able to tell, babies can learn any language on Earth equally easily, as long as they are exposed to it from a very early age.

But the differences could show up more strongly in adults struggling to learn a foreign language.

Also, small differences created as children learn languages can add up over time to transform the way societies communicate.

"Children don't have quite the same language that their parents have," Ladd said. That's why Shakespeare's English is different from today's.

The new study suggests that genes could also play a role in this phenomenon.

"If there was really a gene for tone, you would expect even native speakers of a tone language to vary greatly in terms of their abilities to perceive or use tones in their languages," said Suzanne Flynn, a linguist at the Massachusetts Institute of Technology in Cambridge.

Ladd plans to look for this kind of effect in follow-up studies.