I am absolutely NOT an expert with vocal shepherds, Titan (my boy
nice name btw
) isn't too vocal unless he is meeting someone. I'm sure someone will have better advice for you.. BUT Have you taught him an end all command? I know in the situation where my Titan greets people and won't stop barking or whining, "ENOUGH!" is generally what he needs to stop.. followed by "good boy!" and a reward.
Commander Charly Titan (GSD)-15 Jan 2010