A recent Wall Street Journal Blog article cited a study by Northwestern University researchers that links increased attention span to bilingual speaking people. Here is an excerpt from the article.

Now, in a study published in the Proceedings of the National Academy of Sciences, researchers at Northwestern University for the first time have documented differences in how the bilingual brain processes the sounds of speech, compared with those who speak a single language, in ways that make it better at picking out a spoken syllable, even when it is buried in a babble of voices.

That biological difference in the auditory nervous system appears to also enhance attention and working memory among those who speak more than one language, they say.

“Because you have two languages going on in your head, you become very good at determining what is and is not relevant,” says Dr. Nina Kraus, a professor of neurobiology and physiology at Northwestern, who was part of the study team. “You are a mental juggler.”

In the new study, Kraus and her colleagues tested the involuntary neural responses to speech sounds by comparing brain signals in 23 high school students who were fluent in English and Spanish to those of 25 teenagers who only spoke English. When it was quiet, both groups could hear the test syllable — “da” — with no trouble, but when there was background noise, the brains of the bilingual students were significantly better at detecting the fundamental frequency of speech sounds.

“We have determined that the nervous system of a bilingual person responds to sound in a way that is distinctive from a person who speaks only one language,” Kraus says.

Through this fine-tuning of the nervous system, people who can master more than one language are building a more resilient brain, one more proficient at multitasking, setting priorities, and, perhaps, better able to withstand the ravages of age, a range of recent studies suggest.

This just highlights one of the many benefits of having your child learn a second language.