mouthing

Mouthing is a term used for several related behaviors involving the mouth and speech. In linguistics and clinical contexts, it most often refers to silent articulation—lip, tongue, and jaw movements that resemble speaking but produce no audible voice.

Visible articulatory movements can convey phonetic information, and mouthing is a factor in speech-reading and silent speech research. Some studies use people’s mouthing movements to investigate how much information about speech can be obtained from lip movements alone.

In child development, mouthing describes oral exploration by infants and toddlers, who frequently put objects in their mouths to learn about their environment and to teethe. Most children outgrow this behavior by age two to four; persistent mouthing can raise choking or ingestion risks, leading caregivers to supervise and provide safe toy choices.

In performance contexts, mouthing can describe actors moving their lips while dialogue is provided off-screen or by another performer, or situations involving lip-syncing and dubbing. It can be used to synchronize visual speech with audio or to convey realism when sound is not available.

Etymology traces mouthing to mouth and the -ing suffix. See also lip-reading, silent speech, and oral exploration.