Active & Passive Articulators: /m/ and /d/ Explained

The active articulator for the consonant '/m/' is the lower lip, which actively moves towards the upper lip to produce the sound. The passive articulator is the upper lip, which remains stationary as the lower lip approaches it.

For the consonant '/d/', the active articulator is the tip of the tongue, which moves towards the alveolar ridge (the ridge behind the upper teeth) to create the sound. The passive articulator is the alveolar ridge, which remains stationary as the tip of the tongue makes contact with it.