I think they should just rename the "silence" spell to a more appropriate name in every game that uses such a spell, but the spells require no verbal component.
It is quite obvious that all these games derive their Silence spell from Dungeons & Dragons, in which casting magic often requires a Verbal (spoken), Somatic (hand gestures), and Material (a pinch of sulphur, etc) components to cast a spell. If you block one or all of these components from being used, the spell caster's ability to cast a spell is diminished, but not always eliminated. For example, a Wizard could be silenced, but still be able to cast spells that only had a Somatic component, or if they have any spells prepared with the Silent Casting feat.
I am just out to prove I am the biggest geek in all of geekdom. :cryvaultboy:
I think you're right, actually, because in none of the Elder Scrolls games have spells been shown to involve incantations of any kind. It's just casters waving their hands and particle effects appear and then bam! The spell is cast, and I suppose it's possible that they'll change this in Skyrim, but I doubt it, since they already have abilities similar to magic but seperate which do actually involve words (Namely, dragon shout.) I'd think keeping the approach of not having incantations involved in casting would make more sense as it would serve to further emphasize that dragon shouts and normal spell casting are different. Despite all this, though, even though no incantations are involved in spell casting in the Elder Scrolls games, the spell that prevents spell casting is still called silence and I have no doubt that this is due to the influence of D&D.
Now, back to the subject at hand, it really depends on how silence is supposed to work, if silence in lore actually prevents the target from speaking and thus uttering incantations curiously absent in gameplay, then it should apply to normal dialog as well, if silence works simply by preventing someone from using spells and doesn't actually silence that person, then it should work as before. Though I might suggest that if it's going to be like that, then the name of "silence" be changed to avoid further confusion, or we can even have a seperate spell effect called silene which does what its name implies, keeping the target from speaking, thus preventing him or her from calling for help or reporting your crimes, it should also, logically, prevent the use of dragon shouts.