new spell - enforced eloquence:
A strand of power floats towards the target and slips into his mouth. While under the spell, the target is forced to constantly talk - the topic is irrelevant, it could even be spellcasting, but the target has to keep talking, unless he physically blocks his speech, such as by gagging himself. While the effect lasts, the target's pronounciation and vocabulary are slightly improved - the pell presumably protects from side effects such as strained throat.