Hi everyone - great site about a truly great star.
On the subject of "exceptions" to Harpo's on-stage silence, I thought you might like to see this snippet from the New York Times of 17 August 1936 that I recently discovered:
"SAN FRANCISCO, August 16 (AP). Harpo Marx broke what he said was a 13-year silence when he spoke before a theatre audience here last night. The pantomime specialist of the motion picture and stage trio of brothers came back on the stage after his harp playing drew prolonged applause, and thanked the audience."
I think that this incident took place during the pre-production "vaudeville" tour of material from A Day at the Races. Anyway, its interesting because I have never seen the incident mentioned anywhere else - not even in Simon Louvish's biography of the Marx Bros.