I believe that Aikido can be taught. Not everyone has the ability to see something and figure it out. A student can watch a teacher and mimic them but have they learned? Do they know why a particular move is made? Aikido as I would bet any other martial art can be "STOLEN" from the teacher, but does the student REALLY understand the minute details that make it so? Mostly not I believe. I remember training with my Sensei and teaching my students, and how I sometimes mimiced the technique but did not understand why or how it worked and I see the same thing in my students. I will say after some years of training I learned to see the intricacies of the techniques as my students are now doing. So we may not TEACH the whole but we are TAUGHT to learn.
As for being a talkative teacher or being a silent one. I do both... it depends on the class and how everyone is doing. To me being a GOOD teacher is having the knowledge but more important the ability to communicate your knowledge in a variety of ways to get to the same point.
In sincere Aiki spirit,