André Classe writes a much earlier ethnography of La Gomera’s “Silbo” in 1957 where some of the terms used for descriptions are quite dated. The paper authoritatively sates the historical proto whistling languages that existed before colonisation were employed by the indigenous peoples of the island… “the Guanches, had developed a whistled form of language for communication in their territory, there so thickly wooded that whistles were the only kind of “talk” which could be transmitted for any kind of distance.”

We know that silbo is a proxy language, still it remains impressive how well La Gomera’s Spanish dialect has been adapted to fit within the limitations of whistling. Standard Spanish like the other Latin derived languages has many variables to produce sonic objects that create consonants and vowels: Larynx, lips, tongue and teeth. Silbo’s only method of phonetic ability lies primarily from use of the tongue… Whistlers rest the tip of their tongue against the back of the upper teeth and modulate the shape of the tongue in accordance with the way vowels and constantans are formed in La Gomera’s Spanish dialect.

Classe explains how pitch is the one and only variable that “silbadors” have at their disposal to express what they want to state. “For articulating words, duration and loudness are unimportant, because duration has little significance in Spanish and you always whistle at the “top of your voice” in order to be heard at distance.” This is no unremarkable feat when considering the complexity of the Spanish language with consonants and vowels being condensed into whistled sound objects presented as minute variations in pitches, constant tones and breaks in whistled sequence. English holds much more complex phonetics, for example, a word like “embellish” marrying sound objects like “mmmm”, “li”, “shh” which could equate to a much different whistling language system. 

This theorem is solidified through Julien Meyer’s research papers comparing whistling languages from different cultures and locations.   

Upon understanding the linguistic device’s utilitarian intention to carry messages across ravines, it is clear why pitch makes perfect sense to be the primary phonetic variable. Speech’s complex harmonics and timbres sits within many different bands of the spectrum. For instance, plosives such as “p” and “b” rely on a much lower frequency and harder transients charged by trapped air behind the lips, then released. Details this complex can be lost over distance and through foliage. In contrast, a whistle’s timbre quality is similar to a sine wave which is ideal in that unlike harmonically rich sounds which may lose resonant frequencies through physical objects and distance, as long as the simple sine wave like tone is heard, the listener only has to determine pitch to decode the message. 

An important point made is the similarity between sound objects representing consonants however in practice of Silbo this fragmented unambiguousness is irradicated because of the context in how sentences and phrases fit amongst each other distinctly.  

Classe’s paper displays an old perception of silbo that no longer exists today as it was written at a time when the language was used much more regularly by the island’s inhabitants naturally due to the lack of telecommunication technologies introduced gradually in the years after its publication, thus the language saw a major decline in use up until the late 90s where it was made a part of school curriculum. 

What is interesting about old silbo is how fragmented upon the small island the language seemed to be as Classe claims “silbo is differentiated into different dialects” … “When we played back recordings, the whistlers would invariably claim their own performances, saying something like: “Ah, that’s my silbo” -implying that it was much better and clearer than anybody else’s.”  It’s demise throughout the latter half of the 20^th century and resurgence from close to the start of the 21^st has channelled only a small and specific vein of “dialect” as it was primarily taught at this time by few of the last “silbadors” keeping the language breathing at a time when it seemed to be on the brink of extinction.