The inhabitants of La Gomera have an ancient way of communicating across deep ravines by means of a whistled speech called "Silbo Gomero", which can be heard 2 miles away. This whistled language is indigenous to the island, and its existence has been documented since Roman times. Invented by the original inhabitants of the island, the Guanches, "Silbo Gomero" was adopted by the Spanish settlers in the 16th century and survived after the Guanches were entirely assimilated. When this means of communication was threatened with extinction at the dawn of the 21st century, the local government required all children to learn it in school. Marcial Morera, a linguist at the University of La Laguna has said that the study of silbo may help understand how languages are formed.