Whistled language

Whistled languages use whistling to emulate speech and facilitate communication. A whistled language is a system of whistled communication which allows fluent whistlers to transmit and comprehend a potentially unlimited number of messages over long distances. Whistled languages are different in this respect from the restricted codes sometimes used by herders or animal trainers to transmit simple messages or instructions. Generally, whistled languages emulate the tones or vowel formants of a natural spoken language, as well as aspects of its intonation and prosody, so that trained listeners who speak that language can understand the encoded message. English speakers experience something similar when they listen to sine-wave speech.

Whistled language is rare compared to spoken language, but it is found in cultures around the world. It is especially common in tone languages where the whistled tones transmit the tones of the syllables (tone melodies of the words). This might be because in tone languages the tone melody carries more of the functional load of communication while non-tonal phonology carries proportionally less. The genesis of a whistled language has never been recorded in either case and has not yet received much productive study.