One time, with my whole family (after a wedding) of over 100 of us in Chicago, we decided that for a minimum of ten minutes, ten minutes, we would try and talk in quieter tones and not use our hands. My cousin, Nancy, probably the most "wish I was born in Ireland" of us, couldn't last! She was using her hands within two minutes! Beyond that, we all started laughing and that took out the volume control! Of course, it being after the wedding celebration, and it being a celebration of one our birthdays, needless to say we were all quite jubilant!
but indeed, it must be construed as a speech impediment to not use your hands. After spending so much time with my family that summer (the whole summer in Chicago, it was awesome) and then going back to high school, I was picked on quite a bit by my friends. It actually took one of my teachers, Brother Acquinas (of the Holy Order of St. Patrick, and born in N. Ireland) to come to my defense! It was the first and only time anyone else realized that great man had a sense of humor!