The Borgu Musical Pounders or The Talking Mortars.

   Whether for domestic or commercial purpose pounding as you know is a stressful activity. The Baatonu women in the video(pounding Shea nut.) are displaying one of the age-long Heritage of the Great Borgu Kingdom by which women motivate themselves and eliminate the fatique and boredom associated with pounding. It's practiced among Baatonu women in particular.
   In those day, ladies especially the married ones with partners uses this method in responding to themselves to settle scores in the never ending game of rivalry. The pounding women takes the initiative and begin the process by pounding in proverbs and the other woman whose senses must have gotten the message passed by the pounder. It could be used to sing the praises of their loved ones, geneology, or their sons/daughters.
The ponding is technical and not ordinary because there are syntax which must be followed by the pounder in order to make a meaningful sound while the other listen carefully and decode/decode the sound to prepare for her own turn to pound. However, the woman at the receiving end(decoder) will have to wait till her turn to cook in the like-manner(pounding) and she will respond to the first pounder's message(abuses) and the pounding therefore goes on and on.