In most cases containing physical gestures is key to effective public presentations. Looking like a windmill, arms flailing, is generally not recommended, at least in most American public forums.
But consider the rest of the world – in particular Italy – where experts say some 250 different gestures are used in everyday conversation. Arm and hand gestures add inflection, passion, and emphasis, and are an important and even expected part of effective communication in that country.
Truth is, culture should very much be a consideration when preparing for public speaking. We at CommCore train our American clients speaking in business meetings to hold their hands in what we call the “ski pole” position – standing straight, forearms at waist level with hands apart, relaxed and open. Move hands for occasional emphasis with palms open, and don’t let your movements be so brusque as to become a distraction.
But when in Rome, should we not do as the Romans? When presenting in public in Italy or other Latin countries, should we not put our fingers to our lips and exaggerate a kiss if we approve of a point? Should we not raise our hands in mock supplication when asking a rhetorical question?
The American Communications Association's Open Knowledge Guide to Public Speaking notes in its analysis of communications patterns that in non-verbal communication, "People all over the world use their hands, heads, and bodies to communicate expressively. Nonverbal messages are often the primary means of relating our emotions, our attitudes, and the nature of our relationships with others. Nonverbal messages can express what verbal messages cannot express and are assumed to be more truthful than verbal messages."
In the end, we subscribe to the ACA's conclusion in their report: "Remember, communication always takes place between individuals not cultures, but understanding cultural orientations will always help you become an effective speaker."
Just be sure you know your audience.