Kiduttaja
Consul
100% correct: in the "mordacchia" picture three inserts are shown. The flat one is just blocking the tongue movements, while the n. 2 is a bit more "demanding".The spikes were used not only to make speaking difficult but also to "teach a woman control over her tongue". This meant that she had to keep her tongue flat and loose to avoid contact with the spikes.
In the additional pics I put some more sexy masks: