Remove the following from the official Special Purpose Artist list / guidelines

[dialogue] - Used for soundtrack tracks which consist solely of excerpted dialogue. Example: the "Royale with Cheese" discussion from Pulp Fiction would be correctly assigned to [dialogue], not to "John Travolta & Samuel L. Jackson". Their performances within the track should instead be indicated by vocal relationships.

Move the name to the "subset of unknown" section, to be used only when the performer of the dialog is unknown.