It was well known that the superior temporal sulcus (STS) of our brain, integrates auditory and sensory information, but now scientists from MIT and Duke have established that STS is also responsible for the timing of spoken language.

The timing of speech is one of the core elements of the human spoken language and scientists have successfully identified the regions in our brain that control it. The phonemes are the smallest and most rudimentary elements of speech that usually lasts from 30 to 60 milliseconds. Syllables however take around 200 to 300 milliseconds while complete words take even longer. Tobiasa Overath, an assistant research professor of psychology and neuroscience at Duke, believes that our auditory system must have some sort of mechanism to filter and process the massive amounts of information it receives. It takes chunks of information and groups them together based on the average length of a consonant and syllable.

In order to test which specific regions of our brain played the most vital role in processing the timing of our speech, the scientists went to great lengths to ensure that the test results were reliable and accurate. The researchers re-created ‘speech quilts’ by taking recordings of foreign speech and then rearranging it by grouping the dialogue into smaller portions ranging from 30 to 960 milliseconds. The resized portions were then completely rearranged using an original algorithm to ensure that the sequence of the test ‘speech quilts’ were completely novel. Scientists used magnetic resonance imaging machine to scan and record the participants’ brain for real time neuron activity. The hypothesis of this test was that the parts of the brain that were involved in speech processing should show increased responses to speech quilts which comprised of longer segments.

The superior temporal sulcus (STS) became very active when the speech quilts ranging from 480 to 960 milliseconds were played in comparison to the 30 milliseconds quilts. The other regions of the brain showed little or no activity at all during the various speech quilts. “This was pretty exciting. We knew we were onto something,” commented an ecstatic Overath.

The researchers went further to ensure that the test results were not anomalies by repeating the experiment with various artificially created control sound quilts that resembled speech, such as sounds lacking rhythms, pitch from natural human speech. And as expected the STS did not respond to these artificial sound quilts.