Obstruents

 

Manner of articulation 

Based on how air flows through the vocal tract, consonants can be broadly divided into obstruents and sonorants. Obstruents are consonants produced with an obstruction of the airflow, and sonorants, with little obstruction of the air flow. 

Obstruents

Most consonants are obstruents. With obstruents, there is turbulence in the airflow as the air flow is obstructed or restricted in some manner. Depending on the manner of restricting the air flow, obstruents can be further divided into three types: plosives (or stops), fricatives, and affricates. Most obstruents occur as voiced and voiceless pairs, with two sounds being produced identically from a mechanical standpoint. That is, they occur in the same place and in the same manner. Their only difference is the use or non-use of the vocal cords. 

Plosives (stops)

Plosives or stops are sounds that are made by popping the air, like popping a balloon. When popping, we exhale breath, and this process is called aspiration. To make the pop, we first need to stop the air stream entirely. This explains why plosives are also called stops. And then we release the air all at once. There are 7 plosive sounds, which are /p/, /b/, /t/, /d/, /k/, /g/ and the glottal stop (/ʔ/). The glottal stop is not a phoneme of English, but it is used for a special case, as an allophone of /t/, which we learn in the section on /t/. Plosives are all produced by the same method: stop the air, and then pop the air. They differ in where the stop happens. For the /p, b/ pair, the stop happens at the lips. For the /t, d/ pair, the stop happens at the tooth ridge, which is also called the alveolar ridge. For the /k, g/ pair, the stop happens at the velum. And for glottal stop (/ʔ/), the stop happens at the glottis. For this glottal stop, the space between the vocal cords is closed completely (very briefly), and then released. We can find the glottal stop when we say the expression ‘uh-oh!’ Within the pairs, /p, t, k/ are voiceless, and /b, d, g/ are voiced. Sounds are called ‘voiced’ when the vocal cord vibrates while the sounds are produced. 

Fricatives

Fricatives are sounds that are made by friction. It is like air escaping from a hole in a balloon. For fricative consonants, two parts of the vocal tract, such as the tongue and the teeth, come very close to each other, making a very small narrow opening for air to escape. Air hisses through the small space in-between. So the final sound is a friction-like hissing sound. The air stream is never completely blocked, so the sound can continue. There are 9 fricatives, which are /f/, /v/, /θ/, /ð/, /s/, /z/, /∫/, /ᴣ/, and /h/. 

For /f/ and its voiced counterpart /v/, air escapes through the space between the top teeth and lower lip. For /θ/ and its voiced counterart /ð/, air escapes through the space between the top teeth and the tongue. For /s/ and its voiced counterpart /z/, the tip of the tongue is close to the alveolar ridge, making a narrow space between the tip of the tongue and the bottom of the top teeth. Air escapes through that space. For /∫/ and its voiced counterpart /ᴣ/, the sides of the tongue touch the sides of the upper teeth. The tip of the tongue does not touch anything. The blade of the tongue is concave, making the tongue look like a rain gutter. The lips are close together and protruding. Air comes out through the channel created by the concave part of the tongue. 

/ʃ/ is used in ‘Confucian’ and /ʒ/ is used in ‘confusion.’ /h/ is produced through friction in the vocal cords. /h/ is unvoiced, as the vocal cords do not vibrate during the production of this sound. To create the /h/ sound, the deep back of the tongue slightly constricts within the throat. 

Affricates

Affricates are made by combining a stop with a fricative. The mouth is closed at first, as in a stop, then it opens a little bit into position for a fricative. So an affricate is a stop with a slow release. For instance, try to say the word ‘cheese.’ You should notice that your tongue is in the position to make a /t/ sound. But instead of releasing the air entirely quickly, you release it only partially and turn it into a fricative, thus resulting in the sound /tʃ/. Its voiced counterpart is /ʤ/. Try to say the word ‘jeez.’ You begin with the stop /d/, and then release the air slowly to become a /dʒ/. English has only the two affricates: /ʧ/ and /ʤ/.