When Hashem spoke to the world at the giving of the law at mount Sinia it was Pentacost 50 days after passover and G-d hovered over the heads of the multitude in a great flame.G-d spoke to the children of Israel and the stranger who sojurned with them.When G-d spoke ,he spoke in everymans language and the people feared G-d and told Moses{Don't let G-d speak to us again} I believe on that day that Hashem spoke to the entire world proclaiming himself as the one true G-d. At pentacost he also hovered over the heads of the desciples in order to speak through them to everyman in every toungue known to man