(n.) One who, or that which, spouts.

Philadelphia lawyer apologist arguer argufier casuist controversialist declaimer demagogue disceptator disputant guardhouse lawyer haranguer jawsmith logomacher logomachist mooter panelist pilpulist polemic polemicist polemist public speaker rabble-rouser ranter speaker speecher speechifier speechmaker spieler spokesman spokeswoman spouter talker tub-thumper wrangler