What are the role of teeth in speech production?

The teeth work with the lips, and with the tongue and palette to form sounds. In some instances, the teeth form a "solid wall" to mark out the inner boundary of the mouth, and the facial muscles pull the lips taught over the teeth. The "B" sound normally has the lips curling over the shape of the teeth to form the sound. In forming the "F" and "V" sounds, the lower lip is actually pressed to the upper teeth to shape them. In the "S" sound, the teeth trap the air and work with the tongue to form it. The "Z" sound is made with the teeth together and some help from the tongue. We can make a "J" sound without the teeth, but we usually don't. (Try it!) Same with the "L" sound. Experiment with this and see what you can and cannot do. Then come back and edit this post for correctness and accuracy. It will be appreciated by any and all who read it.