Definition of "prattler"

“I am glad, Nanny,” says Mrs Miller, “the gentleman hath made the observation; I protest I am almost of his opinion. What can be the matter with you, child? I never saw such an alteration. What is become of all your gaiety? Would you think, sir, I used to call her my little prattler? She hath not spoke twenty words this week.”

1749, Henry Fielding, The History of Tom Jones, a Foundling