Celebrim
Legend
If you shouldn't need to "have" the skill to play a PC with that skill, as it defeats the point.
I agree. You raise all sorts of issues which could take us off in all sorts of directions. I'd like to try to stay on one subject for the moment instead of debating what it means to 'role play' or what the purpose of alignment was or where the understanding of how to play out a personality comes from, or any number of other things which may be interesting but which don't get us any closer to understanding or agreement on this topic.
What this gets down to, is from a mechanical sense, what you as a player actually say has no mechanical support in the rules, except in establishing the intent of your PC.
And again I agree, but there in is also the rub in claim. There are very few rules the game that have mechanical support for when the rule applies. We know that the proposition, 'I climb', is relevent when the object of the climb is established (a tree, a wall, an ogre) and is agreed to exist in the imaginary space. Even then, more information may be required to understand the player's purpose. "I climb the tree" and "I climb the wall" are altogether vague propositions. As the referee, I might understand, "I climb the wall" to mean, "I climb the wall to the top". But, if I apply a similar understanding to, "I climb the tree.", and mechanically respond, "Eventually the tree limbs become to weak to support your weight, and they break and you fall.", then I'm relying on false (and bad) understanding of the player intent. If I don't understand the player's intent, I might prompt the player for more information like, "How far up the tree do you wish to climb?"
So establishing player intent is always important and usually not at all obvious. It sometimes requires several exchanges before I can narrow down what is meant sufficiently to rule on it, and even then there can be disagreement over whether the response I made as a DM is appropriate to the intention of the proposition. You have to be very careful, for example, to know whether a player has entered a room, or whether, "I look at the chest." means merely looking or actively investigating by touch.
The problem with a statement of intent like, "I speak diplomatically to the dwarf.", or even, "I attempt to persuade the dwarf to sell me a hammer." is that the dwarf is much much more complicated than either a wall or a tree, and therefore it is much much more necessary that the intent of the player in interacting with the dwarf be pinned down precisely. While it is possible that I could in many cases exchange clarifications with the player to understand the intent and nature of a social interaction, ultimately this is a very imprecise method and in the case of a social interaction very time consumnig relative to the amount of information that is exhanged.
By far the best solution to the problem in my experience is to have the player declare the content of his social interaction as best as he is able. The style of the delivery doesn't have to match what his player is capable of, but the content needs to be there before I can in anyway respond to it in a way that matches my intention for the NPC to be a fully realized, cinematic character that advances a story.
So, yes:
Essentially, regardless of how eloquent you were, the GM should establish what you want from the NPC and go by the roll of the dice. Because there are no rules to abjudicate your acting ability.
I agree with that, but I don't think agreement with that precludes the need for the player to speak in his character's 'voice'. Yes, I agree that the character might be more or less eloquent than the player, but as a DM I have to know the content of the interaction. "I attempt to persuade the dwarf to sell me a hammer.", tells me the DM so much less about your action than speaking into the shared imaginary space does, that I simply will make no attempt to resolve such an action.
The reason that there is no rules for this is that human social interaction is so fantastically complicated that its virtually impossible to create useful rules for it. The ability to create rules to judge human verbal content would be equivalent to the ability to create a Turing capable conversational AI.
Besides which, interacting in the imaginary space is so much more fun than interacting solely with the rules, that I feel cheated when you don't.