From Scientific American:
The act of hearing is a group effort for the human body's organs, involving the ears, the eyes and also, according to the results of a new study, the skin. In 1976 scientists discovered the importance of the eyes to our sense of hearing by demonstrating that the eyes could fool the ears in a peculiar phenomenon named the McGurk effect. When participants watched a video in which a person was saying “ga” but the audio was playing “ba,” people thought they heard a completely different sound—”da.” Now, by mixing audio with the tactile sense of airflow, researchers have found that our perception of certain sounds relies, in part, on being able to feel these sounds. The study was published November 26 in Nature.
Normally when we say words with the letters “p,” “t” and “k,” we produce a puff of air. This puff helps the listener distinguish words with these letters from those with the similar sounding “b,” “d” and “g,” respectively, even though the puff is so subtle that most of us do not even notice feeling it. “Unless you're a microphone manufacturer or a radio jockey or a phonetician, this isn't something that you're aware of,” says Bryan Gick, an associate professor of linguistics at the University of British Columbia in Vancouver, and lead author of the study. Donald Derrick, a graduate student in the University's Department of Linguistics, is the other author on the study.