Finally, I think in watching old films of O'Sensei and other famous instructors, they are constantly explaining how to perform the techinque, and describing the mechanics.
Actually, from what I've seen in most of the articles at Aikido Journal, it seem Ueshiba Sensei didn't talk much about technique. He would show a technique, and then let people practice it. The talking was usually about esoteric shinto and other things, and people mostly just wanted the old man to shut up so they could train.
Ron (search for the kobukan dojo days articles)