Verbose: using or containing too many words; "long-winded (or windy) speakers"
Levin smiled joyfully; he was struck by this transition from the
confused, verbose discussion with Pestsov and his brother to this
laconic, clear, almost wordless communication of the most complex
Anna Karenina by Tolstoy, Leo
Garrulous: Given to excessive and often trivial or rambling talk; tiresomely talkative.
Often, when they had no more agreeable occupation at hand, the Misses
Murray would amuse themselves with visiting the poor cottagers on
their father's estate, to receive their flattering homage, or to hear
the old stories or gossiping news of the garrulous old women
Agnes Grey by Bronte, Anne
Prolix: Tediously prolonged; wordy:
"The manner is indifferent," interrupted Inez, too anxious to await
the prolix explanations of the old man; "why is the visit made?
The Prairie by Cooper, James Fenimore
An ineffectual speaker: Someone whose speech lacks forcefulness or effectiveness; weak
Or more simply a bore: One that is wearingly dull, repetitive, or tedious.