The Collaborative International Dictionary of English v.0.48:

Talkative \Talk"a*tive\, a.
   Given to much talking.
   [1913 Webster]

   Syn: Garrulous; loquacious. See Garrulous.
        [1913 Webster] -- Talk"a*tive*ly, adv. --
        Talk"a*tive*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

talkative
    adj 1: full of trivial conversation; "kept from her housework by
           gabby neighbors" [syn: chatty, gabby, garrulous,
           loquacious, talkative, talky]
    2: unwisely talking too much [syn: bigmouthed,
       blabbermouthed, blabby, talkative]
    3: friendly and open and willing to talk; "wine made the guest
       expansive" [syn: expansive, talkative]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "talkative":
   accessible, all jaw, apocalyptic, approachable, articulate,
   betraying, candid, chatty, communicative, conversable,
   conversational, de longue haleine, demonstrative, disclosing,
   disclosive, effusive, eloquent, endless, expansive, exposing,
   extended, extroverted, eye-opening, filled out, flip, fluent,
   frank, free, free-speaking, free-spoken, free-tongued, gabby,
   garrulous, gassy, glib, gossipy, gregarious, gushy, lengthy, long,
   long-drawn-out, long-spun, long-winded, longiloquent,
   loose-tongued, loquacious, loud-speaking, loud-spoken, mouthy,
   multiloquent, multiloquious, newsy, open, outgoing, outspoken,
   overtalkative, padded, plain-speaking, plain-spoken, prolix,
   protracted, revealing, revelational, revelatory, self-revealing,
   self-revelatory, showing, smooth, sociable, soft-speaking,
   soft-spoken, speaking, spun-out, talking, talky, true-speaking,
   unconstrained, unhampered, unrelenting, unrepressed, unreserved,
   unrestrained, unrestricted, unreticent, unsecretive, unshrinking,
   unsilent, unsuppressed, verbose, vocal, voluble, well-spoken,
   windy, wordy