Definify.com

Webster 1913 Edition

Noun.

The quality of being chatty, or of talking easily and pleasantly.

chattiness ‎(uncountable)

the state of being chatty
- 1841 Catherine Grace F. Gore - Greville: or, A season in Paris
  The sole object of his chattiness at table was to prevent a more intimate conversation between herself and her companion.
- 1997 Michael L. Frankel - Cruising the Gulags
  . . . but I felt good about having left the radio on anyway, even if it was just to satisfy my American chattiness.