Click Languages Sharpen the Ear for Hidden Conversational Sounds, Study Finds

Every language has its hidden soundtrack. Beyond the words and grammar that linguists traditionally study, speakers sprinkle their conversations with small non-verbal noises: a sharp intake of breath, a lip smack, or the famous “tsk-tsk” of disapproval. Among these, click sounds occupy a special place. They are produced with a suction mechanism that most consonants never use, and they punctuate everyday speech in languages from English to Swedish to Mandarin Chinese. Yet a growing body of research suggests that most listeners barely register that these clicks exist, even when they hear them constantly. A new study published in Frontiers in Language Sciences asks a striking question: does the language you grow up speaking change how well you can hear them?

The answer, according to a team spanning South Africa, France and the United States, appears to be yes, at least in part. Kyle Seakgwa of the University of the Western Cape, Sharon Peperkamp and Emmanuel Chemla of the Laboratoire de Sciences Cognitives et Psycholinguistique in Paris, and Derrin Pinto and Donny Vigil of the University of St Thomas in Minnesota, found that people who grew up speaking languages with phonemic clicks, such as Zulu or Xhosa, are better than monolingual English speakers at spotting paralinguistic clicks buried in English speech. The advantage is modest, and it emerges only under specific conditions, but its very existence offers a rare window into how linguistic experience shapes auditory perception in ways that go far beyond vocabulary and grammar.

To understand why this matters, it helps to distinguish the two kinds of clicks that linguists study. Phonemic clicks are full-fledged consonants in a small number of languages, estimated at roughly 0.5 percent of the world’s languages, nearly all of them in Africa. These sounds are acoustically and articulatorily complex: they involve a double place of articulation, with constrictions at both the front and back of the mouth held simultaneously, and they rely on a non-pulmonic airstream mechanism in which the tongue creates a vacuum and the release of the front constriction produces a characteristic popping or suction noise. Anyone who has listened to Xhosa or Zulu knows how salient these consonants are; they leap out of the speech stream even to untrained foreign ears.

Paralinguistic clicks are a different beast. They occur in many, perhaps all, languages, but they are not part of any phonemic inventory. Phonetically, they lie outside ordinary consonant systems; grammatically, they are not integrated into morphology or syntax; and semantically, they carry a narrow range of meanings, often tied to emotion or discourse management. A dental click in English can signal disapproval, while a click at the start of an utterance can mark that the speaker is searching for a word or launching a new sequence of talk. Researchers have documented such clicks in English, Spanish, French, German, Hebrew, Russian, Swedish and Mandarin Chinese, typically articulated with the tongue tip against the alveolar ridge or teeth, with a simultaneous velar closure. Less common variants include bilabial clicks, similar to blowing a kiss, and lateral clicks resembling the sound some cultures use to urge on a horse.

Despite their ubiquity, paralinguistic clicks are astonishingly hard to detect consciously. In a 2020 study, Vigil and Pinto showed native English speakers pairs of short video clips of semi-spontaneous speech, one containing a search click and one in which the click had been digitally silenced. Participants were asked whether they noticed any difference in the speaker’s oral expression and, if so, to report the timestamp. They succeeded in fewer than 20 percent of cases, a figure the authors argued was below chance. The result was puzzling because paralinguistic clicks are acoustically prominent: they typically occur during pauses and stand out against low-salience fillers like “um.” If listeners cannot hear such a conspicuous sound, something interesting must be happening in the perceptual system.

The new study set out to test whether speakers of click-using languages, which the researchers abbreviate as CU languages, show heightened sensitivity to these sounds. The team administered the same click detection task online, using the identical stimuli and procedure as the original experiment. Eight video clips of nine to ten seconds each, drawn from a scientific presentation by a native American English speaker, were paired so that one clip contained a paralinguistic search click and the other had the click silenced. Four additional distractor pairs contained no clicks at all. Participants watched each pair, separated by a five-second interval, indicated whether they perceived a difference, and if so reported the timestamp of that difference. Crucially, the click removal happened only in the audio track, a detail participants were deliberately not told.

The first experiment recruited 118 monolingual English speakers from the United States through the online platform Prolific, with the design and analyses pre-registered in advance. The researchers refined the original study’s statistical approach in two ways. First, they adopted a more stringent chance level of about 17 percent, reasoning that a participant has roughly a one-in-two chance of claiming any difference exists and approximately a one-in-three chance of landing the timestamp within one second of the click in a nine-to-ten-second clip. Second, they used bootstrapping with 1,000 resamples to estimate 95 percent confidence intervals, allowing a principled assessment of how plausible the null hypothesis really is. A detection was counted as timely only if the participant both correctly reported a difference and placed it within one second of the click.

The English speakers’ performance was strikingly poor. Mean timely detection on target items was just 11 percent, even lower than the 17.4 percent reported in the original classroom-based study, and statistically indistinguishable from the stringent chance level in both the opening condition, where clicks began a sentence, and the mid condition, where they appeared mid-sentence. Accuracy was also lower than in the original study for sentence-initial clicks, which the authors suggest may reflect the challenges of online testing compared with a controlled classroom setting. Yet the picture was not entirely bleak. The confidence interval for timely detections did not include zero, participants reported more differences in target pairs than in distractor pairs, and they described hearing the presence or absence of a click-like sound only in response to target pairs. The researchers conclude that English speakers’ capacity to detect paralinguistic clicks is weak, but not null.

The second experiment turned to South Africa, where Prolific offers no direct filtering by click language, so participants were initially selected as South-born and resident English-speaking multilinguals. Of 124 people tested, 54 reported speaking at least one CU language and were included in the analysis: 46 spoke Zulu, 16 Xhosa, 14 Sotho, 9 Swati and 3 Ndebele, with 27 speaking two or more of these languages. Using the same stimuli and procedure, these participants again showed overall low detection rates, performing no better than chance on sentence-medial clicks. But on sentence-initial clicks, their performance was significantly better than that of the monolingual English speakers, and their responses showed a clearer separation between target and distractor pairs, including click mentions that were entirely absent from distractor trials.

Why would the advantage be confined to clicks at the beginning of sentences? The researchers offer a tantalizing hypothesis rooted in phonology: click consonants in CU languages tend to appear at the beginning of words, so speakers of these languages may have tuned their attention to the positions where clicks are most likely to occur. The broader implication is that the presence of phonemic clicks in a person’s native language yields a perceptual advantage for non-linguistic clicks, at least when listening to a language the person speaks as a second language. The effect is small, and it survived despite an adversarial online setting and short stimuli, which makes its detection all the more notable.

Many questions remain. The team used only search clicks embedded in emotionally neutral speech, leaving open whether stance clicks in emotive-laden speech would be easier to catch. Audiovisual stimuli were chosen to prevent confusion between clicks and mouse clicks, yet audio-only presentation might make detection easier, as one study of the filler “um” suggests. And because all participants listened to English, a language they all knew, the researchers cannot rule out that detection would improve in an unknown language, where clicks are known to be highly salient even to listeners who speak nothing like them. What the study establishes is that the sounds we learn to treat as meaningful consonants reshape how we parse the incidental noises of conversation. In roughly half a percent of the world’s languages, clicks do grammatical work; everywhere else, they whisper at the edges of meaning. This research shows that where clicks live in a language determines, quite literally, what the ear learns to hear.

Subject of Research: Cross-linguistic differences in the auditory detection of paralinguistic click sounds in conversation

Article Title: Cross-linguistic variation in the detection of conversational click sounds

Article References: Seakgwa, K., Peperkamp, S., Pinto, D., Vigil, D., & Chemla, E. (2026). Cross-linguistic variation in the detection of conversational click sounds. Frontiers in Language Sciences, 5, Article 1932401. https://doi.org/10.3389/flang.2026.1932401

Image Credits: AI Generated

DOI: 10.3389/flang.2026.1932401

Keywords: click languages, paralinguistic clicks, phonemic clicks, cross-linguistic perception, Zulu, Xhosa, speech perception, bilingualism, psycholinguistics, phonetics, discourse markers, auditory detection