Lipreading, or speechreading is the process in which we try to understand speech by observing the movements of the face, lips, and tongue of a talker. Note that I say we “try” to understand speech. It is not possible to fully understand speech from visual cues alone. Here’s why:
All speech sounds can by classified by three parameters (see chart below): Place, manner, and voicing. Place of articulation refers to where the sound is made. For example, the sounds /p/, /b/, and /m/ are all referred to as bilabials since they are produced using both lips. The sounds /f/ and /v/ are referred to as labiodentals since the lower lip is placed between the teeth. There are a whole bunch of sounds that are produced at the alveolar ridge, which is the little shelf jest behind your two front teeth. With these sounds, the tongue is placed on this ridge. The remaining sounds are produced further back in the mouth and are pretty much invisible to the eye. These include sounds such as /sh/, /ch/, /g/, /k/, and /h/.
|Stops||Voiced||/b/ bet||/d/ dent||/g/ goat|
|Voicedless||/p/ pet||/t/ tent||/k/ coat|
|Fricatives||Voiced||/v/ vet||/th/ these||/z/ zed||/zh/ garage|
|Voicedless||/f/ fed||/th/ think||/s/ sent||/sh/ sheep||/h/ hot|
|Nasals||Voiced||/m/ met||/n/ net||/ng/ bang|
|Liquids||Voiced||/l/ let||/r/ reap|
|Glides||Voiced||/w/ wet||/y/ yell|
The other two parameters are manner and voicing. Manner refers to the type of sound produced. For example, fricatives sound like air rushing or hissing. Stops or plosives sound like a burst of sound. It is very hard to see the manner of a consonant.
Voicing refers to the use of our vocal folds when we make a sound. Try this little experiment. Place your hand on your throat and make the /f/ sound and then the /v/ sound. Don’t say these letters, make the sound. You will feel your vocal folds vibrating for the /v/ sound, but not the /f/ sound. This is of course invisible to the eye; we cannot see vocal folds vibrating.
Now lets look again at the sounds /p/, /b/, and /m/. All three of these sounds will look pretty much the same via lipreading. However they certainly sound different and more importantly, they change the meaning of the word. If I say “pat”, “bat”, and “mat”, one cannot see the difference between these words.
So the reason that communicating exclusively via lipreading is difficult is due to two main reasons. First, many sounds are produced at the back of the mouth and are completely invisible. Examples include /h/, /g/, /k/, /ng/. Second, many sounds look exactly the same because they are produced at the same place in the mouth. The consonants /p/, /b/, /m/ are a good example of that.
But lipreading can still be useful as a supplement to hearing. Numerous research studies over the years have confirmed this. Most studies show that while the scores of most people on lipreading tasks is typically quite low, it makes a great supplement to the auditory channel such that auditory-visual speech perception (lipreading + hearing) is much greater that auditory only. In fact, I recall reading a study examining auditory only, visual only, and auditory visual speech perception in older adults. Even though these adults scored 0% on visual only speech perception, their auditory-visual speech perception score was still greater than auditory only.
While I consider myself a pretty good lipreader, I have made some amusing errors over the years. Here are some examples of embarrassing mistakes I have made. First sentence is what was actually said, and the second is what I thought was said. It may also reveal the workings of my twisted mind.
What Was Actually Said: My teacher is so cool, she plays the guitar.
What I Thought: My teacher is so cool, she pees in a jar.
What Was Actually Said: I am going to design you a tattoo.
What I Thought: I am dying to touch you.
What Was Actually Said: There is some nice grass over there for your dog.
What I Thought: There is some nice ass over there…
So here is my advice when it comes to lipreading:
- Use it as a supplement to your hearing.
- Hearing is still the most important sense we have for communication via speech.
- If your are finding that you need to lipread a lot in quiet, you should consider getting assessed for a cochlear implant. Lipreading all day long is highly inaccurate and very tiring.
- If you find yourself lipreading a lot when in noise, consider getting a wireless microphone system such as an FM system to help improve the signal to noise ratio. Or get out of the noise.
- Training to improve lipreading skills is debatable. Instead, focus on creating favorable conditions for llipreading. Tune in next time to a discussion on how to enhance the conditions for successful lipreading.