The sounds of certain words make us think of things that are big or small, round or spiky, and the tendency is nearly universal. For example, people can often pick words that refer to something big or small even in languages they don't speak. Here's why.
What sized object comes to mind when you hear a made-up word like "teedee?" Something small or something large? And does "bouba" sounds round or spiky? Fascinatingly, research has found that, even across languages, people often assign very similar meanings to certain types of words because of the way they sound.
Sounds and symbols
This idea of words "sounding" like their meaning is something most people become acquainted with early in life when adults ask children what says "moo" and what says "woof." These words for the noises that animals make are derived from how people perceive the way the noises sound and then try to copy them in speech. Of course, depending on our language system, we hear these animal noises differently, which is why dogs might say "woof" in English, but "wan wan" in Japanese.
Such onomatopoeia, or words that mimic something about the thing they describe, is just the tip of the iceberg in modern sound symbolism research, a field which studies the non-arbitrary relationship of sounds to meaning.
Though the idea of words having an inherent sense had been tossed around by philosophers in antiquity who pondered the nature of meaning, a more scientific look at this topic began in the early 20th century, focusing specifically on the sounds a word contained, rather than the word itself. Since then, there has been a steady stream of work that has pointed to a link between certain sounds and a person’s perception of the properties of objects, like their size or shape.
For instance, in an early experimental study by famed anthropological linguist Edward Sapir, made-up words were used to refer to a table. When told the table was "mal," subjects identified the table as large as opposed to when the table was referred to as "mil," which they associated instead with a small table.
What was behind this strange pattern? Sapir hypothesized that words with vowels pronounced using the front part of the tongue, like "ee" (as in "tea"), were associated with smaller sized objects than words with vowels like "oh" or "ah" made more toward the back of the mouth. Since his early work, this vowel-size correlation has been replicated extensively and, moving beyond just size, later studies have tried to tease out both which sounds seem to trigger specific associations and what they seem to symbolize.
For instance, similar experiments have also examined the relationship between certain vowels, like ‘oh’ and ‘ee,’ and an object’s shape. When asked to match (made-up) names to objects, subjects seem to prefer words with "uw" (as in "boot") or "oh" vowels for round objects (e.g. selecting "maluma" or "bouba"). In contrast, sharp or angular objects get matched up with names that have "ee" and "ey" sounds such as "kiki" or "takete." So, front vowels seem to indicate spiky-ness or angularity, while back vowels are heard as describing smooth or round objects.
Finally, not only do sounds appear to tell us something about size or shape, but they also seem to influence listeners’ emotions. In studies of how different vowel sounds affect emotional states, front vowels like "ee" or "ey" are happier sounding (think "glee" or "peace") than back vowels like "uw" or "oh" (think "gross" or "tomb"). For example, in a recent study, German subjects reported lower mood and pleasantness ratings after saying "euw" vowels. As well, in looking across song lyrics, poems and other types of texts, other research suggests "ee" vowels occur in texts with a more pleasant emotional tone.
Cross-linguistic sound symbolism
Further research in linguistics and psychology explores whether such sound symbolism holds even if we hear words in a language we don’t understand. So, for instance, when an English speaker listens to Chinese, are they still more accurate in guessing a word’s meaning based on the sounds used?
The short answer? Yes. The sounds people often perceive as indicating small versus big or round versus angular shapes tend to be alike across languages. In other words, this sound/size and sound/shape link was not related to any specific language but seemed to be something more universal. In studies with participants who spoke varied languages like English or Japanese, a made-up word with front vowels was consistently taken to describe a smaller object than a word with back vowels regardless of the language background of the listener.
And not only do made-up words exhibit these size and shape predicting vowel patterns, existing vocabularies in languages seem to reflect this trend. In cross-linguistic research, it was found that 90% of languages use "ee" sounds in words to indicate some type of smallness. Think, for example, of how English refers to kids using nicknames with "ee" sounds added to the end, such as Sammy, Freddy, Janie or Susie, but how people often stop using those diminutives when they grow up and become, well, bigger people.
It also seems that these sound-meaning relations can even help decipher what words mean in an unknown language. When speakers of Polish and Italian, for instance, were given words in linguistically unrelated languages like Japanese and Finnish, they were still able to guess the correct meaning of the words (given several choices) at rates better than chance using only the sounds of the words as clues.
Do those vowels come in extra large?
Though it does now seem well established that sounds alone can communicate some aspects of meaning, what might explain why certain sounds communicate particular things like how big or spiky objects are or how happy we are, and why would this be so prevalent across languages?
In the late 20th century, linguist John Ohala proposed the "Frequency Code" hypothesis, drawing on an earlier theory by Darwin that posited that speech emerged from the imitation of sounds in the natural world. Ohala noted the fact that, in the wild, large animals tend to make lower frequency sounds compared to smaller animals, e.g. when a lion roars at a mouse, you generally find the mouse listens. This relationship of pitch to the perception of size emerges because a sound’s frequency is determined in large part by the size of the vocal tract which produces it. Larger animals generally have larger vocal tracts that produce deeper resonances, much like the larger cello produces a deeper sound than a violin.
Drawing on this relationship between loud and large, Ohala suggests that vowels articulated in the back of the mouth and with a more open vocal tract like "oh" or "ah," have a lower frequency so remind us of larger objects, while vowels that have a more front and closed articulation, like "ee" (think "teensy" and "tiny") make us think of smaller and more compact objects. While we don’t utter deep growls at people, or at least not after our first cup of coffee, adopting articulatory positioning to create lower or higher pitched sounds translates what was once a biologically relevant clue (big animal or small animal) into a similar sense of "largeness" or "smallness" associated with that sound.
Another popular theory suggests that our sound-meaning associations stem instead from the phonetic gestures we make when producing sounds. Front vowels (e.g., "ee" and "ey" sounds) involve smaller movements with a closed jaw position while back vowels (e.g., "oh" and "ah" sounds) involve a more open jaw positions resulting in a larger mouth opening. Likewise, making an "oh" or "euw" sounds involves lip rounding, something that might explain why we hear those sounds as rounder or curvier than "ee" sounds that instead involved spread lips. In both cases, speakers learn to associate these embodied senses of a smaller closed mouth or larger open mouth, or sharper or rounder lip position with the sounds they produce.
Regardless of which theory you ascribe to, much of what contributes to our ability to hear sounds in isolation as meaningful does seem to come from the experiences we have tied into speaking those sounds — be it the shape of our mouths resembling round objects as when we say "oh" or "euw" or the lower pitch due to body size of the sound "ah" compared to "ee."
Of course, these sound-meaning correspondences are more on the order of statistical tendencies than obligatory links, as languages have widely divergent pressures on their sound systems over time. For instance, the Great Vowel Shift radically altered the way vowels were pronounced in English at the end of the Middle English period for reasons that had nothing to do with whether we were describing spiky things or small ones. But, even so, it certainly ramps up the pressure when trying to find that perfect sounding name for a new baby or pet.
D'Anselmo, A., Prete, G., Zdybek, P., Tommasi, L., & Brancucci, A. (2019). Guessing Meaning From Word Sounds of Unfamiliar Languages: A Cross-Cultural Sound Symbolism Study. Frontiers in psychology, 10, 593. https://doi.org/10.3389/fpsyg.2019.00593
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