Example time series for a 2 s forward section of all the parameters used for coherence calculation. (A) Example time series of the fundamental frequency extracted with the pitch.m MATLAB function. (B) Example audio signal and the acoustic speech envelope (in blue). (C) Lip area extracted from the video frames with the MATLAB script adapted from Park et al. (2016). (D) Example spectrogram with overlaying formants (F1–F3, red lines) extracted with Praat.