2.6 Classifying Consonants
Consonants are classified according to how they are produced. The articulatory description for each consonant includes three pieces of information, the voicing, the place of articulation, and the manner of articulation.
Let’s look more closely at the class of sounds we call consonants. Remember that consonants have some constriction in the vocal tract that obstructs the airflow, either partially or completely. We can classify consonants according to three pieces of information.
The first piece of information we need to know about a consonant is its voicing — is it voiced or voiceless? In the video about how humans produce speech, we felt the difference between voiced and voiceless sounds: for voiced consonants like [z] and [v], the vocal folds vibrate. For voiceless sounds like [s] and [f], the vocal folds are held apart to let air pass through.
The second thing we need to know about consonants is where the obstruction in the vocal tract occurs; we call that the place of articulation.
If we obstruct our vocal tract at the lips, like for the sounds [b] and [p], the place of articulation is bilabial.
The consonants [f] and [v] are made with the top teeth on the bottom lip, so these are called labiodental sounds.
Move your tongue to the ridge above and behind your top teeth and make a [t] or [d]; these are alveolar sounds. Many people also make the sound [s] with the tongue at the alveolar ridge. Even though there is quite a bit of variation in how people make the sound [s], it still gets classified as an alveolar sound.
If you’re making a [s] and move the tongue farther back, not quite to the soft palate, the sound turns into a [ʃ], which is called post-alveolar, meaning it’s a little bit behind the alveolar ridge. You also sometimes see [ʃ] and [ʒ] called “alveo-palatal” or “palato-alveolar” sounds because the place of articulation is between the alveolar ridge and the palate.
The only true palatal sound that English has is [j].
And if you bring the back of your tongue up against the back of the soft palate, the velum, you produce the velar sounds [k] and [ɡ].
Some languages also have uvular and pharyngeal sounds made even farther back in the throat, but English doesn’t have sounds at those places of articulation.
And of course English has a glottal fricative made right at the larynx, the sound [h].
In addition to knowing where the vocal tract is obstructed, to classify consonants we also need to know how the vocal tract is obstructed. This is called the manner of articulation.
If we obstruct the airflow completely, the sound is called a stop. When the airflow is stopped, pressure builds up in the vocal tract and then is released in an burst of air when we release the obstruction. So the other name for stops is plosives. English has two bilabial stops, [p] and [b], two alveolar stops, [t] and [d], and two velar stops [k] and [ɡ].
It’s also possible to obstruct the airflow in the mouth but allow air to flow through the nasal cavity. English has three nasal sounds at those same three places of articulation: the bilabial nasal [m], the alveolar nasal [n], and the velar nasal [ŋ]. Because airflow is blocked in the mouth for these, they are sometimes called nasal stops, in contrast to the plosives which are oral stops.
Instead of blocking airflow completely, it’s possible to hold the articulators close together and allow air to flow turbulently through the small space. Sounds with this kind of turbulence are called fricatives. English has labiodental fricatives [f] and [v], dental fricatives made with the tongue between the teeth, [θ] and [ð], alveolar fricatives [s] and [z], post-alveolar fricatives [ʃ] and [ʒ], and the glottal fricative [h]. Other languages also have fricatives at other places of articulation.
If you bring your articulators close together but let the air flow smoothly, the resulting sound is called an approximant. The glides [j] and [w] are classified as approximants when they behave like consonants. The palatal approximant [j] is made with the tongue towards the palate, and the [w] sound has two places of articulation: the back of the tongue is raised towards the velum and the lips are rounded, so it is called a labial-velar approximant.
The North American English [ɹ] sound is an alveolar approximant with the tongue approaching the alveolar ridge. And if we keep the tongue at the alveolar ridge but allow air to flow along the sides of the tongue, we get the alveolar lateral approximant [l], where the word lateral means “on the side”. The sounds [ɹ] and [l] are also sometimes called “liquids”
If you look at the official IPA chart for consonants, you’ll see that it’s organized in a very useful way. The places of articulation are listed along the top, and they start at the front of the mouth, at the lips, and move gradually backwards to the glottis. And down the left-hand side are listed the manners of articulation. The top of the chart has the manners with the greatest obstruction of the vocal tract, the stops or plosives, and moves gradually down to get to the approximants, which have the least obstruction and therefore greatest airflow.
In Essentials of Linguistics, we concentrate on the sounds of Canadian English, so we don’t pay as much attention to sounds with retroflex, uvular, or pharyngeal places of articulation. You’ll learn more about these if you go on in linguistics. And you probably noticed that there are some other manners of articulation that we haven’t yet talked about.
A trill involves bringing the articulators together and vibrating them rapidly. North American English doesn’t have any trills, but Scottish English often has a trilled [r]. You also hear trills in Spanish, French and Italian.
A flap (or tap) is a very short sound that is a bit like a stop because it has a complete obstruction of the vocal tract, but the obstruction is so short that air pressure doesn’t build up. Most people aren’t aware of the flap but it’s actually quite common in Canadian English. You can hear it in the middle of these words metal and medal. Notice that even though they’re spelled with “t” and “d”, they sound exactly the same when we pronounce them in ordinary speech. If you’re trying hard to be extra clear, you might say [mɛtəl] or [mɛdəl], but ordinarily, that “t” or “d” in the middle of the word just becomes an alveolar flap, where the tongue taps very briefly at the alveolar ridge but doesn’t allow air pressure to build up. You can also hear a flap in the middle of words like middle, water, bottle, kidding, needle. The symbol for the alveolar flap [ɾ] looks a bit like the letter “r” but it represents that flap sound.
When we’re talking about English sounds, we also need to mention affricates. If you start to say the word cheese, you’ll notice that your tongue is in the position to make a [t] sound. But instead of releasing that alveolar stop completely, like you would in the word tease, you release it only partially and turn it into a fricative, [tʃ]. Same thing for the word jam: you start off the sound with the stop [d], and then release the stop but still keep the articulators close together to make a fricative [dʒ]. Affricates aren’t listed on the IPA chart because they’re a double articulation, a combination of a stop followed by a fricative. English has only the two affricates, [tʃ] and [dʒ], but German has a bilabial affricate [pf] and many Slavic languages have the affricates [ts] and [dz].
To sum up, all consonants involve some obstruction in the vocal tract. We classify consonants according to three pieces of information:
- the voicing: is it voiced or voiceless,
- the place of articulation: where is the vocal tract obstructed, and
- the manner of articulation: how is the vocal tract obstructed.
These three pieces of information make up the articulatory description for each speech sound, so we can talk about the voiceless labiodental fricative [f] or the voiced velar stop [ɡ], and so on.