What is coarticulation?
- Coarticulation is the way the brain organizes sequences of vowels and consonants, interweaving the individual movements necessary for each into one smooth whole. In fact, the process applies to all body movement, not just speech, and is part of how homo sapiens works.
- It takes about a fifth of a second to produce a syllable, or about a fifteenth or twentieth of a second for each consonant or vowel.
- Now it turns out it takes a little longer than that to move the lips, tongue and jaw for each vowel and consonant. So what is happening?
- The brain coordinates these individual articulator movements in a very ingenious way, such that movements needed for adjacent vowels and consonants are produced simultaneously.
- This results in speech being produced very smoothly.
- At the same time it spreads out acoustic information about a vowel or consonant and helps a listener understand what is being said.
- Speech coarticulation is thus also a very important part of the special code that enables us to speak at five syllables a second.
- For example, suppose you say the word happy on its own:
- Before you say anything, you will start breathing out, and you will have moved your tongue into position for a and started opening your mouth for a
- Then, while you are hissing for h, it will sound a bit like a whispered a
- When you stop hissing for h, you will turn your voice on for a
- When you start saying a, you will continue opening your mouth for a
- Once your mouth is fully open for a, you will start closing it again, and your lips, for pp
- As your lips meet, you will switch your voice off for pp
- While your lips are together for pp, you will be moving your tongue from where you had it for a towards where you need it for y
- As you separate your lips from pp, you will let a tiny puff of air escape between them
- As the puff ends you will turn your voice on for y
- While you start saying y, you will continue to move your tongue to where you need it for y and continue opening your lips after pp
- Once your tongue is in position for y, you will keep it there
- Once your done with y you will switch your voice off, move your tongue away from y, and start breathing in
- The whole word will usually be uttered in less than half a second
- The precise timings might differ collectively between different accents. Some people might have their own individual timings, part of what makes you sound just you. Some people might have deviant timings that reflect some injury or illness requiring the assistance of a speech pathologist.
- Ordinary spelling was used for this example. Linguists and speech pathologists would usually prefer to use some form of phonetic transcription, either between slashes /…/ (an abstract minimal representation in phonemes), or between square brackets […] (for fine pronunciation detail disregarding phonemic abstraction), using the IPA alphabet.
- A typical phonemic transcription might be /ˈhæpi/.
- The first vowel might vary through [ε … æ … a] between different regional accents.
- The second vowel might vary from [i] to [ɪ], while a very conservative British version might be [ε].
- In some accents, /h/ might be dropped.
An example from Bulgarian
Activity for the sequence â r e during the r constriction and the e vocoid:
- The numbers refer to image frames on the X-ray motion film, each representing 13 milliseconds.
- Simultaneous activity for â, r and e during the vibrant r constriction (26-27) and the first part of the e vocoid (28-31)
- Tongue body activity for â (26-27)
- Tongue blade activity for r (26-31)
- Tongue body activity for e (28-31)
- (c) The tongue body posture of the vowel â was still maintained during the vibrant phase of r (frames 26-27).
- (a) The elevated tongue blade of r was withdrawn during frames 28-31 (the first part of the e vocoid segment).
- (b, c) The tongue body was raised towards the hard palate for e during frames 28-31, reaching the e posture in frame 31.