Possible Clues:

• Talent for talking
• Would you have to go to the chattering classes for this ability to run on effortlessly?
• Ability to speak effortlessly
• Present old paper to that man backing case with ability to talk hind legs off a donkey!
• Ability to speak persuasively
• Ability to talk persuasively
• Would you have to go to the talking shop for this present in Blarney?
• Talent for spilling the beans? Such an ability is utterly amazing perhaps
• Talent of eloquence?
• There's a lot to be said for having it