Wiggly Rings

Harmonicas don’t get no respect. They’re cheap (I just found one online for $5), tiny hunks of metal that tend to be played by guys who didn’t finish finishing school. I’ve had a couple of harmonicas for years, and have never understood them: they don’t have all the notes and can only play three chords. Blowing on a harmonica can’t help but sound fairly good, but I have always been frustrated by my inability to get it to do much more. A serious blues harmonica player can create sounds far richer than seems possible from what would appear to be little more than a toy.

A harmonica is deceptive because it is, in a sense, not an entire instrument at all. It is perhaps half an instrument–maybe that’s why they’re so inexpensive. The other half of the instrument is the human hand. That explains why the best harmonica players have hands, and, in addition, tend to move them all about the instrument when playing. This is described as “bending” the notes, and by doing so, the performer can provide a musical dynamism not possible with just the twenty or so notes in the harmonica’s range. The sounds reaching the listener’s ears are not only those coming directly from the harmonica, but also the harmonica sounds that first bounce off objects in the environment before reflecting toward the listener’s ears. For the note‑bending blues performer, the hands are the objects the sounds bounce off. Each time a sound bounces off something, some sound frequencies are absorbed more than others, and so the timbre of the sound coming from that reflection is changed. The total timbre depends on the totality of harmonica sounds that reach the ear directly and indirectly from all points in the environment. And we’re able to hear these sound shapes, which is why harmonica benders go to all the trouble of wiggling their hands–and why there are acoustics engineers who worry about the physical layout of auditoriums.

Bending and acoustic reflections don’t just matter in the blues and in concert halls where instruments (including half instruments) are crooning out musical tones. Objects involved in events also croon, or ring. A ring has a complex timbre that informs us of the object’s size, shape, and material. But just like harmonica sounds, rings can get bent by the environmental surroundings. And our brains can decode the bends, and can give us a sense of our surroundings purely on the basis of the shapes of the sounds reaching our ears. The psychologist James J. Jenkins demonstrated in 1985 that blindfolded students, after a little practice, can navigate very well amongst obstacles by utilizing such auditory cues.

These acoustical observations about how the surroundings affect sound have an important consequence for the internal structure of rings: rings can be wiggly. There are several converging reasons for this. First, an event that causes a ring often also sets the ringing object in motion: something has been hit, or something is sliding. Because the shape of a ring reaching one’s ears depends on the object’s surroundings, ringing objects that are moving produce rings that vary over time. Second, when an event occurs, we are often on the move. Because the shape of the ring we receive depends, in part, upon our position in the world, the shape of the ring reaching our ears may be varying over time. In each case, whether we are moving or the object is, the timbre of a ringing object can change, and these are wiggles we notice, at least subconsciously. In addition to such dynamic changes in the subtleties of a ring’s timbre, there is another dimension in which rings can often vary: pitch, the musical‑note‑like “higher” or “lower” quality of sound. When motion is involved–either our own motion or that of the objects involved in events–we get Doppler shifts, a phenomenon we are all familiar with, as when a car approaching you sounds higher‑pitched than when it is moving away. (See also the later section of this chapter titled “Unresolved Questions” for more about the Doppler effect and its stamp upon speech. And see the following chapters on music, where the Doppler effect will be discussed in detail.)

Rings can therefore change over time, both in timbre and in pitch. That is, a single ring can often be intrinsically dynamic. What about hits and slides?

Hits are nearly instantaneous, and for this simple reason they cannot change over time, at least not in the sense of continuously varying from one kind of hit to another. Hits can, of course, happen in quick succession, such as when you drop a pen and one end hits an instant before the other. But such a pen event would be two physical interactions, not one. Unlike a single ring, which can wiggle, a single hit has no wiggle room.

How about slides? Slides can occur for a lot longer than an instant, and so they can, in principle, dynamically vary over their occurrence. Although slides can be long–for example, a single snowy hill run on a sled may be one continuous slide–they are much more commonly short (though not instantaneous) in duration, because they quickly dissipate the energy of an event, sometimes ending it. Do the sounds of slides ever, in fact, dynamically vary over time? Before answering this, let’s be clear on what we mean by the sound of a slide. A slide can cause a ring, as we have discussed, but that is not what we’re interested in at the moment. We are, instead, interested in the sound made by the physical interaction of the two sliding surfaces–the noisy friction sound itself, caused by the coarseness of the objects involved. Therefore, to produce a wiggly slide, the coarseness of the surface being slid upon would have to vary, so that one friction sound would change gradually to another friction sound. Although coarseness varies randomly on lots of materials, few objects vary in a systematic, graded fashion, and thus slides will tend to have a rather nonvarying sound.

Rings, then, can be wiggly. But not hits, and not slides. If language has culturally evolved to sound like nature, then we would expect that sonorant phonemes (language’s rings) would sometimes be dynamically varying, but not plosives (language’s hits) or fricatives (language’s slides).

Languages do, indeed, often have sonorants that vary during their utterance. Although vowels like those in “sit” and in “set” are nonvarying, some vowels do vary, like those in “skate” and “dive.” When one says “skate,” for example, notice how the vowel sound requires your mouth to vary its shape, thereby dynamically modulating its timbre (in particular, modulating something called the formant structure , where formants are the bands of frequencies emanating from a sonorant). Vowel sounds like these are called diphthongs. Furthermore, sonorant consonants like l , r , y , w , and m demand ring changes. For example, when you say “yet,” notice how during the “y” your mouth dynamically varies its shape. These sonorants incorporate timbre changes. Recall that rings in nature also can change in pitch due to the Doppler effect. Do we find something like the Doppler shift in sonorant phonemes? Yes, in fact, in the many tonal languages of the world (such as Chinese), where vowels may be distinguished from one another only by virtue of how they dynamically vary their pitch during their utterance.

Whereas sonorants are commonly wiggly, effectively making more than one ringing sound during their utterance, no language possesses phonemes having in them more than one hit sound. It is possible in principle to have a single phoneme that sounds like two hits in very quick succession–for example, the “ct” in “ectoplasm”–but while we can make such sounds, and they even occur in language, they are never given building‑block, or phoneme, status.

Are language’s slides like nature’s slides in being non‑wiggly? First, let’s be clear on what it would even mean to have a fricative that varies dynamically as it is spoken. Try saying the sound “fs.” That is, begin with an “f” sound, and then slowly morph it to become “s” at the end. You make this sound when, for example, you say “puffs.” Languages could, in principle, have fricative phonemes that sound like “fs.” That is, languages could possess a single phoneme that has this complex dynamic fricative sound, just as languages possess single sonorant phonemes that are dynamic. One does not, however, find phonemes like this among human languages.

Nature’s rings are wiggly but hits and slides are not, and culture has given us language with the same wiggles: language commonly has sonorant phonemes that dynamically vary, but does not have plosive or fricative phonemes that dynamically vary. Our auditory systems are happy with dynamic rings, but not with dynamic hits or slides, and culture has given us speech that conforms to these tastes.

In addition to looking at dynamic changes within phonemes, we can make similar observations at the level of how phonemes combine into words: languages commonly have words with multiple sonorants in a row, but more rarely have multiple plosives or multiple fricatives in a row. For example, consider the following English words, which I found by perusing the second paragraph of this chapter: “harrowing” possesses six sonorants in a row (a, rr, o, w, i, and ng, the latter of which is a nasal sonorant), “village” has three in a row, “generation” has five in a row, and “eventually” has four in a row. One can find adjacent plosives, like in “packed” (“kt”) and “grabbed” (“bd”), and one can find adjacent fricatives like in “puffs” (“fs”), “gives” (“vz”), and “isthmus” (“sth”), but finding more than two in a row is difficult, and five or six in a row is practically impossible.

We now know how, and how much, each of the three kinds of “event atoms” can vary in sound while they are occurring. We have not, however, considered whether an event of one of these three kinds can ever dynamically change into another kind of event. Could some simple event pairs be so common that we are likely to possess special auditory mechanisms for their recognition, mechanisms language harnesses? We turn to this question next, and uncover a kind of event sufficiently fundamental in physics that it is also found as a fourth kind of phoneme in language.