Motor excitability during visual perception of known and unknown spoken languages

•Native and non-native English speakers can visually discriminate English from an unknown language.•Viewing known speech excites the articulatory motor cortex more than unknown speech.•Viewing known speech excites the articulatory motor cortex more than non-speech mouth movements.•Motor excitability is high during observation of a face not speaking.•Motor excitability does not differ between native and non-native speakers. It is possible to comprehend speech and discriminate languages by viewing a speaker’s articulatory movements. Transcranial magnetic stimulation studies have shown that viewing speech enhances excitability in the articulatory motor cortex. Here, we investigated the specificity of this enhanced motor excitability in native and non-native speakers of English. Both groups were able to discriminate between speech movements related to a known (i.e., English) and unknown (i.e., Hebrew) language. The motor excitability was higher during observation of a known language than an unknown language or non-speech mouth movements, suggesting that motor resonance is enhanced specifically during observation of mouth movements that convey linguistic information. Surprisingly, however, the excitability was equally high during observation of a static face. Moreover, the motor excitability did not differ between native and non-native speakers. These findings suggest that the articulatory motor cortex processes several kinds of visual cues during speech communication.