Coarticulation refers to the overlapping articulatory movements that occur during speech production, which affect how neighboring sounds are pronounced. When speaking, the vocal tract is constantly changing shape to produce different sounds, with the articulators always performing motions for multiple sounds at once rather than individually. This allows for speeds of 10-15 segments per second, making rapid speech possible. Coarticulation also aids speech perception by making the connections between sounds smoother.

1. Coarticulation
By : Zahra Aamir Kamil.

2. Introduction
Coarticulation is the phenomenon of overlapping articulatory movements
that occur during speech production to the way in which the pronunciation
of one sound affects the pronunciation of neighboring sounds.
In other words, when we speak, our vocal tract is constantly moving and
changing shape to produce different sounds.

3. Coarticulation simply means that the articulators are always
performing motions for more than one speech sound at a time.
The articulators do not perform all the work for one speech
sound, then another.
The genius of speech production is that phonological segments overlap, so
the articulators work at maximum efficiency, in order to be able to
produce 10 to 15 phonetic segments per second more in rapid speech.

4. This transmission speed would be close to impossible to
achieve if each phonological unit were produced individually.
As it is, speech is produced more slowly than necessary for the
speech perception system.

5.  coarticulation is not just a matter of convenience for the
speaker:
 If speech were not coarticulated .
 If phonological units did not overlap.
Speech would actually be too slow and disconnected for the hearer
to process it efficiently.

6. The articulation of [k] in key and coo.
When uttering key :
 The back of the tongue is making closure with the top of
the mouth for the [k].
 The lips not ordinarily involved in articulating [k]
 begin to spread in anticipation of the following vowel [i].
when uttering coo
The lips round during the articulation of [k], in anticipation of the upcoming [u].

7. One aspect of coarticulation is that the actual articulation of
a phonological segment can be influenced by upcoming sounds.
This is sometimes referred to as regressive assimilation.
Coarticulation can also be influenced by a phonological segment
that has just been produced, a phenomenon sometimes called
progressive assimilation.

8. The [t] in seat is
pronounced slightly more forward in the mouth than the [t] in suit.
This is because the tongue position for the [t] is influenced by the preceding
vowel ([i] is a front vowel and [u] is a back vowel).

9. Coarticulatory effects can span several segments.
[b] in bag will be articulated slightly differently than the [b] in
bat, as a consequence of the differences in the syllable final
phonemes [ɡ] and [t].
 In the process of speaking, phonemes overlap and blur
together.

10. One final aspect of coarticulation is central to understanding
the production (and perception) of stop consonants.
Stops involve producing a complete closure somewhere in the
vocal tract:
[p] and [b] involve closure at the lips.
[t] and [d] closure at the alveolar ridge.
[k] and [ɡ] closure at the velum.