Approximately 80 low-density and remote populations around the world still use whistled speech, yet only around 40 of them have been studied or recorded, according to the latest peer-reviewed tally (see section 1). Whistled speech is used at distances of around 50 m to 2 km, while click consonants, the other extreme of human sound-making, appear in just 10 of 566 languages (1.8%) in the WALS sample (WALS Online, chapter 19). The click languages that do exist range from Hadza, with some one thousand speakers (CNRS News 2020), to isiZulu, the household language of 24.4% of South Africans (Stats SA, Cultural Dynamics in South Africa 2025). Both systems push speech to its acoustic limits, a theme that also runs through our roundup on birdsong pitch shifts in urban noise. We aggregated data from Frontiers in Psychology, UNESCO Intangible Cultural Heritage, the World Atlas of Language Structures (WALS), Current Biology, the Journal of the Acoustical Society of America, Interspeech, Statistics South Africa, and a dozen other primary sources.
TL;DR
- At least 80 cultures have developed whistled versions of their local language (Knowable Magazine 2021).
- Skilled whistlers can reach 120 decibels, and whistled speech can be understood up to 10 times as far away as shouting (Knowable Magazine 2021).
- Silbo Gomero joined UNESCO’s Representative List in 2009 and has been taught in schools since 1999 (UNESCO Intangible Cultural Heritage).
- Nearly 10,000 people in Turkey’s Eastern Black Sea Region can speak or understand whistled Turkish (Turkish Ministry of Culture and Tourism).
- Sfyria, whistled Greek, survives in a village of under 30 residents with an estimated 5 proficient whistlers (Interspeech 2025, Batchelder-Schwab et al.).
- Clicks occur in 10 of 566 languages (1.8%) in the WALS sample (WALS Online, Maddieson, chapter 19).
- Nǀuu has 45 click consonants out of 73 consonants (Miller et al., Working Papers of the Cornell Phonetics Laboratory 2007).
- Botswana Yeyi has the largest Bantu click inventory, with 22 contrastive clicks (Sands and Gunnink, Language Science Press 2019).
- isiZulu and isiXhosa, both click languages, are the household languages of 24.4% and 16.3% of South Africans (Stats SA, Census 2022 results).
- The central alveolar click has the lowest spectral centre of gravity, at around 1000 Hz (Miller and Shah, Interspeech 2009).
1. How Many Whistled Languages Exist
The headline count keeps rising, but not because more people are whistling. In 2004, twelve whistled languages had been partially described and as many as sixty more were suspected; the latest peer-reviewed tally puts approximately 80 populations on the map, with around 40 of them studied or recorded (Frontiers in Psychology 2021). The gap between “reported” and “documented” is the real story: roughly half of the reported whistled systems have not yet been studied or recorded.
Discovery is still happening. Whistled Greek was a “relatively recent discovery in 1980”, and whistled TshiVend̯a in South Africa had been described in a single sentence by musicologist Percival Kirby in 1937, with no further work until fieldwork in 2023 (Boston University Global Development Policy Center 2023).
| Metric | Value | Source |
|---|---|---|
| Populations worldwide using whistled speech / of which studied or recorded | Approximately 80 / around 40 | Meyer, Magnasco and Reiss, Frontiers in Psychology 2021 |
| Whistled languages partially described / additional languages suspected of having a whistled form (2004 count) | Twelve / as many as sixty | Meyer, Anais da Academia Brasileira de Ciências 2004 |
| Cultures that developed whistled versions of the local language | At least 80 | Knowable Magazine 2021 (Holmes) |
| Mazateco language variations in the highlands of Oaxaca, Mexico / variations recorded in whistled form | 14 / 4 | Meyer, Anais da Academia Brasileira de Ciências 2004 |
| Whistled Greek (Sfyria) first discovered | 1980 | Batchelder-Schwab, Michos and Barnes, Interspeech 2025 |
| Whistled TshiVend̯a: first written description / next documentation | One sentence in 1937 / fieldwork in 2023 | Boston University GDP Center 2023 |
Context note: the 2004 counts are the most recent available data from that survey; the 2021 figure is the latest peer-reviewed global tally we could verify.
2. Whistle Range: Distance, Loudness, and Frequency
Whistled speech exists because it beats the human voice outdoors. Whistlers typically talk across around 50 m to 2 km, with common median distances of 400-500 m, and the signal concentrates high power between 800 and 4000 Hz. That band sits above the pitch of most background noise, which helps explain why a whistle carries where a shout fades. For comparison, the decibel levels people reach when raising their voice in noisy rooms are covered in our roundup on restaurant noise and Lombard speech.
The loudness figures are striking: 130 dB at 1 m from the whistler’s mouth in a 2004 bioacoustic survey, and 120 decibels for skilled whistlers in later reporting (Knowable Magazine 2021, republished by Inverse). In non-tonal languages, vowels map onto pitch: the farther whistlers need to communicate, the higher the vowel frequencies, with /i/ staying below 4 kHz and the lowest vowel above 1 kHz (Meyer, Dentel and Meunier, Frontiers in Psychology 2017).
| Metric | Value | Source |
|---|---|---|
| Typical whistled communication distance / common median distance | Around 50 m to 2 km, depending on the place / 400-500 m | Meyer, Magnasco and Reiss, Frontiers in Psychology 2021 |
| Frequency band in which whistles carry high power | 800 to 4000 Hz | Meyer, Magnasco and Reiss, Frontiers in Psychology 2021 |
| Maximum range reported in the mountains of La Gomera | Up to 10 km | Meyer, Anais da Academia Brasileira de Ciências 2004 |
| Sound level measured 1 m from the whistler’s mouth | 130 dB | Meyer, Anais da Academia Brasileira de Ciências 2004 |
| Sound level reached by skilled whistlers | 120 decibels | Knowable Magazine 2021 |
| Distance at which whistled speech is understood, compared with ordinary shouting | Up to 10 times as far | Knowable Magazine 2021 |
Context note: the 10 km figure is a maximum under favourable mountain conditions, while 50 m to 2 km describes everyday use. A 2015 Cell Press release on whistled Turkish says villagers switch to the whistled form at a distance of, say, 50 to 90 meters (Cell Press via ScienceDaily), which fits the low end of that range.
3. Intelligibility and the Learning Curve
A whistle strips speech down to a single melodic line, yet listeners still decode most of it. In René-Guy Busnel’s tests, whistled Turkish isolated words were recognized at approximately 70%, rising to approximately 80-90% for common sentences. Context does the heavy lifting: the sentence frame restores what the reduced signal loses.
Naive listeners also beat chance. In a four-choice whistled-vowel test with 20 native Spanish speakers and 20 native Standard Chinese speakers (one excluded from analysis), an expert whistler scored 87.5% while the naive groups scored 43.5% to 55%, against a 25% chance level. Language structure shapes the whistle too: Chinantec in southern Mexico has seven tones that pitch can carry, while Gavião in the Amazon has just two tones, low and high (Knowable Magazine 2021). The brain treats the whistle differently as well: a Ruhr-University Bochum team tested 31 inhabitants of Kuşköy and found that both hemispheres played significant roles in the early stages of understanding whistled Turkish (Ruhr-University Bochum release on Current Biology 2015).
| Metric | Value | Source |
|---|---|---|
| Whistled Turkish recognition: isolated words / common sentences | Approximately 70% / approximately 80-90% | Meyer, Magnasco and Reiss, Frontiers in Psychology 2021 (citing Busnel) |
| Messages successfully understood in tests: Silbo of La Gomera / Bai tonal language of China | 95% / 80% | Meyer, Anais da Academia Brasileira de Ciências 2004 |
| Expert whistler, whistled vowel categorization | 87.5% correct answers | Meyer, Dentel and Meunier, Frontiers in Psychology 2017 |
| Naive listeners, mean correct answers: Spanish / French / Standard Chinese speakers | 53% / 55% / 43.5% (chance 25%) | Meyer, Dentel and Meunier, Frontiers in Psychology 2017 |
| Silbo course milestones: loud whistle with different pitches / first words / speaking properly and understanding every message | First two or three months / fourth or fifth month / after eight months | Knowable Magazine 2021 (David Díaz Reyes) |
| Kuşköy residents tested with dichotic listening (different syllables played into each ear at the same time) | 31 | Ruhr-University Bochum, Current Biology 2015 |
Most recent available data: the Turkish recognition rates come from Busnel and colleagues’ early studies, and the 95% Silbo figure from Busnel et al. 1962b, both as cited in later reviews.
4. UNESCO Protection and Speaker Numbers
UNESCO has recognized two whistled languages (Knowable Magazine 2021), and their listings tell opposite stories. The Silbo Gomero sits on the Representative List, backed by school teaching since 1999 and a community of more than 22,000 La Gomera inhabitants (UNESCO, Silbo Gomero element 00172). Turkey’s whistled language went onto the Urgent Safeguarding List in 2017, with mobile phone use named as one of the key threats (UNESCO, Whistled language element 00658).
At the far end sits whistled Greek: a single village of under 30 residents and an estimated 5 proficient whistlers (Batchelder-Schwab, Michos and Barnes, Interspeech 2025). Funding is modest even where protection works: the Cabildo (island government) of La Gomera gives the University of La Laguna’s Silbo Gomero chair, a dedicated research and teaching unit, 35,000 euros a year (Universidad de La Laguna 2025). For the wider picture of language loss, see our endangered languages statistics.
| Metric | Value | Source |
|---|---|---|
| Silbo Gomero inscribed on the UNESCO Representative List | 2009 (session 4.COM) | UNESCO Intangible Cultural Heritage |
| Silbo Gomero: Spanish vowels / distinct vowel whistles; consonant whistles | 5 / 2; 4 | UNESCO Intangible Cultural Heritage |
| Whistled language of Türkiye inscribed on the Urgent Safeguarding List | 2017 (session 12.COM, Jeju, December 4-9, 2017) | UNESCO; Turkish Ministry of Culture and Tourism |
| People in Turkey’s Eastern Black Sea Region able to speak and/or understand whistled Turkish | Nearly 10,000 | Turkish Ministry of Culture and Tourism |
| Sfyria (whistled Greek) home village population | Under 30 residents | Batchelder-Schwab, Michos and Barnes, Interspeech 2025 |
| Proficient Greek whistlers today | Well below ten, cautiously estimated at 5 | Batchelder-Schwab, Michos and Barnes, Interspeech 2025 |
| Annual funding for the Silbo Gomero university chair / initial agreement term | 35,000 euros / four years | Universidad de La Laguna, May 22, 2025 |
Context note: the Turkish estimate comes from the Turkish Ministry of Culture and Tourism, which names Giresun, especially its Çanakçı district, as the main stronghold. UNESCO’s own element page gives no speaker count. The Interspeech 2025 study recorded 3 whistlers and 1,075 analyzed tokens, and found 43 of 45 whistled vowel pairs significantly distinguishable on some acoustic measure.
5. Where Click Consonants Occur
Clicks are the rarest consonant class in the WALS sample: 10 of 566 languages, or 1.8%, against 45 languages with labial-velars and 21 with pharyngeals (WALS Online, chapter 19, Maddieson). The chapter places clicks in all the Khoisan languages of southern Africa (five in its sample: !Xóõ, Ju|‘hoan, //Ani, Deti, and Khoekhoe), in three East African languages, and in Bantu languages that borrowed them through contact, independently in an eastern area (Zulu) and a western one (Yeyi).
That borrowing flips the speaker math. The older click-language groups are small (Hadza has some one thousand speakers), but isiZulu and isiXhosa together are the household languages of 40.7% of South Africans (24.4% plus 16.3%, our sum of the two Stats SA figures). Speech technology has been slow to follow, a gap covered in our roundup on low-resource language speech recognition coverage.
| Metric | Value | Source |
|---|---|---|
| Languages with clicks in the WALS sample | 10 of 566 (1.8%) | WALS Online, chapter 19 (Maddieson) |
| Languages with labial-velars / pharyngeals in the same sample | 45 / 21 | WALS Online, Map 19A |
| Khoisan languages of southern Africa in the WALS sample, all with clicks | 5 | WALS Online, chapter 19 (Maddieson) |
| East African languages with clicks (Sandawe, Hadza, Dahalo) | 3 | WALS Online, chapter 19 (Maddieson) |
| Southern African languages spoken by Khwe and San with click repertoires | About 30 | Knight et al., Current Biology 2003 |
| Hadza speakers in Tanzania | Some one thousand | CNRS News 2020 |
| South Africans whose household language is isiZulu / isiXhosa (Census 2022) | 24.4% / 16.3% | Stats SA, Cultural Dynamics in South Africa 2025 |
| isiZulu share in KwaZulu-Natal households / isiXhosa share in Eastern Cape households | 80.0% / 81.8% | Stats SA, Cultural Dynamics in South Africa 2025 |
Context note: the genetic study by Knight et al. in Current Biology 2003 found that click-speaking Hadzabe and Juǀ’hoansi are separated by a genetic distance as great or greater than that between any other pair of African populations, and concluded that clicks may have persisted for tens of thousands of years. Census figures: Stats SA, Cultural Dynamics in South Africa, Report 03-01-84.
6. Click Inventories: How Many Click Phonemes
Inventory size separates the core click languages from the borrowers. Nǀuu has 45 click consonants out of 73 consonants in total, and it is one of only three languages, with ǃXóõ and ǂHoan, reported to contrast all five click types; no language is reported to contrast more than five (Miller et al., The Sounds of Nǀuu, Working Papers of the Cornell Phonetics Laboratory 2007). The count multiplies because each click type combines with accompaniments such as voicing, nasality, and aspiration.
Bantu borrowers use fewer click types but can still build large inventories: Botswana Yeyi has 22 contrastive clicks, and the Nguni languages and Namibian Yeyi have between 10 and 20 (Sands and Gunnink, Clicks on the fringes of the Kalahari Basin Area, 2019). Lexicon share shows the real gap: clicks occur in 14% of the Zulu lexicon and 17% of Xhosa, while in all core Kalahari Basin languages more than 50% of the lexicon contains a click, with an average of 68%.
| Metric | Value | Source |
|---|---|---|
| Nǀuu click consonants out of all consonants (the rest: 25 pulmonic, 3 glottalic) | 45 of 73 | Miller et al., Working Papers of the Cornell Phonetics Laboratory 2007 |
| Maximum click types contrasted by any reported language | Five | Miller et al., Working Papers of the Cornell Phonetics Laboratory 2007 |
| ǃXóõ total consonant contrasts | 119 | Miller et al., Working Papers of the Cornell Phonetics Laboratory 2007 |
| Botswana Yeyi contrastive clicks (largest Bantu click inventory) | 22 | Sands and Gunnink, Language Science Press 2019 |
| Xhosa / Zulu click phonemes | 18 / 15 | Sands and Gunnink, Language Science Press 2019 |
| Southern Sotho click phonemes / share of lexicon with clicks | 3 / 3-5% | Sands and Gunnink, Language Science Press 2019 |
| Hadza consonants / of which clicks | 65 / a dozen | CNRS News 2020 |
| Damin (ritual register of Lardil, Australia) click inventory | Five click sounds | Moisik and Dediu, Journal of Language Evolution 2017 |
Data watch for this table: the SADiLaR African Language Grammar Portal counts 15 click speech sounds in isiXhosa, three of them basic, against 18 click phonemes in Sands and Gunnink; the gap reflects how accompaniments are counted. Nǀuu is still spoken by fewer than ten people in the Northern Cape Province of South Africa, per Miller et al. (most recent available data: 2007).
7. Acoustic and Anatomical Properties of Clicks
Click types are told apart mostly by where the burst’s energy sits. The dental click’s spectral centre of gravity is around 4000 Hz for female speakers, while the central alveolar click is the lowest, at around 1000 Hz for all speakers, in a study of four Mangetti Dune !Xung speakers (Miller and Shah, The Acoustics of Mangetti Dune !Xung Clicks, Interspeech 2009). Spectral centre of gravity is the average frequency of the burst’s energy, a single number that summarizes whether a click sounds sharp or hollow.
These contrasts can erode. In Tsua, a critically endangered Eastern Kalahari Khoe language, the alveolar and palatal click bursts do not differ significantly on spectral moments, burst duration, or intensity, while in Juǀ’hoan the same pair differs significantly on all measures (Mathes and de Voogt, Studies in African Linguistics 2023). Anatomy may also play a role: biomechanical modelling suggests a palate without a prominent alveolar ridge lowers click effort, though the authors say further research is required (Moisik and Dediu, Journal of Language Evolution 2017).
| Metric | Value | Source |
|---|---|---|
| Spectral centre of gravity, dental click | Approximately 4000 Hz (female speakers), approximately 3000 Hz (male speakers) | Miller and Shah, Interspeech 2009 |
| Spectral centre of gravity, palatal click | 2500-3000 Hz (female speakers), 1500-2000 Hz (male speakers) | Miller and Shah, Interspeech 2009 |
| Spectral centre of gravity, lateral click | Around 2000 Hz | Miller and Shah, Interspeech 2009 |
| Spectral centre of gravity, central alveolar click | Around 1000 Hz for all speakers | Miller and Shah, Interspeech 2009 |
| Burst duration of noisy clicks in Naro | Closer to 30 ms | Miller and Shah, Interspeech 2009 |
| Palates classified as convex: 110 male !Kung San vs 138 males from Kenya and Uganda | 57.3% vs 26.1% | Moisik and Dediu, Journal of Language Evolution 2017 (citing an earlier palate survey) |
| Change in total muscle force, most altered palate simulation vs baseline, free jaw: clicks vs velar stops | 7.56% vs 0.00% | Moisik and Dediu, Journal of Language Evolution 2017 |
| Lingual cavity volume method: ultrasound frame rate / production stages / coronal click types | 114 fps / five / four | Miller, Journal of the Acoustical Society of America 2015 |
Context note: the Journal of the Acoustical Society of America abstract by Miller (2015) estimates how the air pocket trapped between the tongue and the roof of the mouth changes size across five stages of click production, combining 3D-digitized palate casts with ultrasound. Most recent available data for the !Xung measurements: 2009.
Summary: Whistled Languages and Click Consonants by the Numbers
| Metric | Value | Source |
|---|---|---|
| Cultures that developed whistled versions of the local language | At least 80 | Knowable Magazine 2021 |
| Annual funding for the Silbo Gomero university chair | 35,000 euros | Universidad de La Laguna, May 22, 2025 |
| Southern Sotho click phonemes | 3 | Language Science Press, Sands and Gunnink 2019 |
| Sound level reached by skilled whistlers | 120 decibels | Knowable Magazine 2021 |
| Sfyria (whistled Greek) home village population | Under 30 residents | Interspeech 2025 |
| Kuşköy residents tested in the whistled Turkish brain study | 31 | Ruhr-University Bochum, Current Biology 2015 |
| Silbo Gomero UNESCO inscription | 2009 | UNESCO Intangible Cultural Heritage |
| Whistled language of Türkiye, Urgent Safeguarding List | 2017 | UNESCO Intangible Cultural Heritage |
| People able to speak or understand whistled Turkish | Nearly 10,000 | Turkish Ministry of Culture and Tourism |
| Proficient whistlers of Sfyria (whistled Greek) | Cautiously estimated at 5 | Interspeech 2025 |
| Languages with clicks in the WALS sample | 10 of 566 (1.8%) | WALS Online, chapter 19 |
| Southern African Khwe and San languages with clicks | About 30 | Current Biology, Knight et al. 2003 |
| Nǀuu click consonants | 45 of 73 consonants | Working Papers of the Cornell Phonetics Laboratory, Miller et al. 2007 |
| Largest Bantu click inventory (Botswana Yeyi) | 22 contrastive clicks | Language Science Press, Sands and Gunnink 2019 |
| Core Kalahari Basin languages: average share of words with clicks | 68% | Language Science Press, Sands and Gunnink 2019 |
| South Africans with isiZulu / isiXhosa as household language | 24.4% / 16.3% | Stats SA, Census 2022 results |
| Hadza consonants / of which clicks | 65 / a dozen | CNRS News 2020 |
| Spectral centre of gravity, central alveolar click | Around 1000 Hz | Interspeech 2009, Miller and Shah |
Methodology and Sources
We ran targeted searches across whistled-speech typology, bioacoustics, UNESCO listings, click typology, click phonetics, and census data, then read each primary document directly. Figures seen only in search snippets or in secondary blogs without a named source were dropped. Language names and phoneme symbols are kept as each source prints them, except that the vertical-bar click letter is written as ǀ inside tables so the table layout does not break.
- Meyer, Magnasco and Reiss, The Relevance of Human Whistled Languages for the Analysis and Decoding of Dolphin Communication, Frontiers in Psychology 2021
- Meyer, Dentel and Meunier, Categorization of Natural Whistled Vowels by Naive Listeners of Different Language Background, Frontiers in Psychology 2017
- Meyer, Bioacoustics of human whistled languages, Anais da Academia Brasileira de Ciências 2004
- Holmes, Knowable Magazine 2021, republished by Inverse
- UNESCO, Whistled language of the island of La Gomera (Canary Islands), the Silbo Gomero
- UNESCO, Whistled language (Türkiye), Urgent Safeguarding List
- Turkish Ministry of Culture and Tourism, Whistled Language
- Ruhr-University Bochum release on Güntürkün, Güntürkün and Hahn, Whistled Turkish alters language asymmetries, Current Biology 2015
- Cell Press release on the same study, via ScienceDaily, August 17, 2015
- Batchelder-Schwab, Michos and Barnes, Stress in Spoken and Whistled Greek, Interspeech 2025
- Boston University Global Development Policy Center, Documenting Whistled Languages in South Africa, 2023
- Universidad de La Laguna, Silbo Gomero chair agreement, May 22, 2025
- WALS Online, Maddieson, Presence of Uncommon Consonants, chapter 19
- Knight et al., African Y chromosome and mtDNA divergence provides insight into the history of click languages, Current Biology 2003
- Miller et al., The Sounds of Nǀuu: Place and Airstream Contrasts, Working Papers of the Cornell Phonetics Laboratory 2007
- Sands and Gunnink, Clicks on the fringes of the Kalahari Basin Area, Language Science Press 2019
- SADiLaR African Language Grammar Portal, Inventory of click sounds (isiXhosa)
- Statistics South Africa, Cultural Dynamics in South Africa, Report 03-01-84, 2025
- CNRS News, fieldwork on Hadza and Iraqw consonants, May 13, 2020
- Miller and Shah, The Acoustics of Mangetti Dune !Xung Clicks, Interspeech 2009
- Mathes and de Voogt, A spectral moments analysis of Tsua and Juǀ’hoan alveolar and palatal click consonants, Studies in African Linguistics 2023
- Moisik and Dediu, Anatomical biasing and clicks, Journal of Language Evolution 2017
- Miller, A method for estimating lingual cavity volume in click consonants, Journal of the Acoustical Society of America 2015
- Data watch: whistled-language counts depend on the threshold for “documented” (twelve partially described in 2004, approximately 40 low-density populations in a 2017 paper, approximately 80 populations with around 40 studied in 2021). Distance figures run from a 50 to 90 meter switch point in whistled Turkish, to 50 m to 2 km for typical use, to a 10 km La Gomera maximum. Loudness is 130 dB at 1 m in the 2004 survey versus 120 decibels in the 2021 magazine report, and the power band is 800 to 4000 Hz (2021), 1 to 4 kHz (Knowable Magazine) or a narrow band typically located between 1000 and 3000 Hz (2004). UNESCO describes two vowel whistles for the five Spanish vowels, while a figure in the 2021 Frontiers paper illustrates four different vowel levels of a same whistler. The WALS chapter text gives a 566-language sample while the Map 19A value table totals 567. isiXhosa has 18 click phonemes per Sands and Gunnink and 15 click sounds per SADiLaR. Many core figures predate 2023 and are the most recent available data; the 40.7% isiZulu plus isiXhosa share is our own sum of two Stats SA percentages.
Last updated: November 8, 2026. We update this roundup quarterly, and the next refresh is expected when the next round of UNESCO Intangible Cultural Heritage periodic reports (due June 30, 2027) is published.