The isolation of the Mexican town San Pedro Sochiapam, nested deep in the Oaxaca mountains, has probably helped to preserve its most famous cultural asset: A unique whistle language that enables people to communicate like birds.
"I think that it's been around ever since this town existed," said Marcelino Flores, a 67-year-old farmer, who studies the local Chinanteco language.
"A relative of my wife's who was 100 recently died, and she said that ever since she was small the police would call each other by whistling," Flores said.
San Pedro's "whistle language," known locally as El Chiflido, is actually a whistled form of the Chinanteco language.
When they whistle, chiflido users emulate the tonal sounds of Chinanteco, an indigenous language with 14 tonal combinations that sounds somewhat like Thai to the untrained ear.
Marcelino Flores is one of the last users of the whistled form of Chinanteco
Chiflido users can whistle thousands of ideas over long distances, and hold a complex conversation without uttering a single word.
"People in other towns are amazed at our ability to whistle, its something that makes me proud" said Flores, who has been visited by linguists from New Zealand, Canada and the U.S.
Like many indigenous tongues in Mexico however, the chiflido is slowly retreating into extinction. Flores estimates that some 150 people in San Pedro can use the chiflido. But Mark Sicoli, a Georgetown University linguist who specializes in Chinanteco, says that he found just seven senior citizens and two young people who were fluent in the whistle language.
“If one of those guys gets work out of town, then the language is under threat,” Sicoli said in a phone interview.
Part of the problem is that the whistle language no longer suits the lifestyle of local residents.
Its main purpose according to linguists, is to enable communication between farmers who are separated by long distances and deep valleys. It is also used by hunters who split away from each other, as they chase animals in the forests that surround San Pedro.
However, as the residents of San Pedro turn away from an agricultural lifestyle and migrate to cities, the chiflido is not as needed.
The Mexican government hasn't done much to rescue this tradition either, unlike Spain, which has invested heavily in saving a rare whistle language used in the Canary Islands.
Currently there is no program to teach the chiflido in the local school. And women don't practice the whistle language because locals consider it improper for females to whistle.
"Young men can do some whistling, but it's a weak form of whistling that goes no longer than 30 feet," Flores said.
"I am afraid this tradition is going to disappear."
But there is some hope.
See the above video for more on this unique whistle language, and two young people who are actually using it.