Articulatory Phonetics 101: Laterality

This is Part 7 of a series covering the basics of articulatory phonetics, the study of how humans physically produce speech sounds. For the full list of posts, see the Articulatory Phonetics 101 Index.

If you’ve read all the previous Articulatory Phonetics 101 posts so far — and you should, if you haven’t — you’ll notice we’ve covered most of the consonants of the English language, with two notable exceptions: /l/ and /w/. In order to understand these two consonants, we have to introduce some additional concepts: laterality and double articulation. In this video, we’ll look at laterality.

Now, say “la la la la” — and hold on the final “l”.

La la la llllllll…

Let’s examine what’s happening in the vocal tract. You can put the back of your hand against your throat to check if it’s voiced — it is. So it’s a voiced consonant.

What about the place of articulation? Well, your tongue is touching the alveolar ridge, so let’s call it alveolar. Let’s try and figure out what the manner of articulation is. It’s not a stop, because the airstream isn’t being stopped behind the tongue. It’s not a fricative, because there’s no turbulence in the airflow. Well, it must be an approximant — but the tongue is touching the alveolar ridge, so that can’t be it either.

Remember, all these different dimensions we’ve constructed so far — phonation, place of articulation, manner of articulation — they’re all just ways to describe what’s happening to the airstream in the vocal tract. We’ve found something that our current model doesn’t accurately describe. So, let’s take a step back and pay attention to the airstream. What’s happening to the airstream in the mouth?

We can compare it with some of the manners we’ve already learnt about. Alternate between /l/ and /t/ for a moment, but don’t release the /t/ — just let the air pressure build up behind the tongue. So it just sounds like this:

lllllll. lllllll. lllllll.

You can feel the airstream being stopped behind the tongue when you say /t/, but air is flowing over the sides of the tongue in /l/.

This is called laterality, from the Latin word latus, meaning “side”, and a lateral consonant is one where airflow is directed over the sides of the tongue, rather than down the middle. So we call /l/ a “voiced alveolar lateral approximant”.

The opposite of lateral is central: all the consonants we looked at in previous posts are central consonants. Central consonants are the “default” — if there’s no specific mention of a consonant being a lateral consonant, you can assume it’s central. So if someone says “voiced alveolar approximant”, that’s always /ɹ/. If you want to specify /l/, you have to call it a “voiced alveolar lateral approximant”.

Now, /l/ is not the only lateral consonant. You can change the manner of articulation to get fricatives like /ɬ/ or /ɮ/, which are the voiceless and voiced alveolar lateral fricatives, or affricates like /tɬ/ or /dɮ/, the voiceless and voiced alveolar lateral affricates. Stops and nasals, however, are never lateral.

You can also change the place of articulation, to get, for example, /ʎ/, the voiced palatal lateral approximant, or /ɭ/, the voiced retroflex lateral approximant, or /ʟ/, the voiced velar lateral approximant.

Okay, that’s all for laterality. In the next post, we’ll look at double and secondary articulation, and then we’ll have covered the consonants of English. After that, we’ll move on to the consonants of the world’s languages that are still not adequately explained by the framework we’ve laid out so far.