What is the difference between active articulators and passive articulators?

In articulatory phonetics, articulators are the speech or vocal organs (above the larynx) that take part in articulation or production of sound. Articulators are divided into two types:

1. Active articulators

2. Passive articulators

Consonant sounds are produced when there is an obstruction of the airflow somewhere in the vocal tract. This obstruction is the point of contact between an active articulator and a passive articulator.

As the name suggests, active articulator is that organ which “moves” and passive articulator is that organ which that remains “stationary” or passive during articulation. Hence, during articulation, the active articulator moves towards the passive articulator and causes complete or partial obstruction of the flow of air in the vocal tract.

The tongue can be called as the main active articulator because the tip, the front, the back and the root of the tongue act as active articulators in the production of most of the sounds. For example, the tip of the tongue touches the alveolar ridge during the production of alveolar sounds like /t/, /d/, etc. Lower lip can also act as an active articulator during the production of bilabial sounds like /p/, /b/, /m/, etc. and labio-dental sounds like /f/, /v/, etc. Passive articulators occur in continuum in the vocal tract. Examples of passive articulators are alveolar ridge, soft palate, hard palate, etc. The speech sounds are mainly named after the passive articulators.