"Omni" means "All" in Greek; "Glot" means "Having as tongue", also in Greek.
The receptionist at the United Nations must be an omniglot.
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Omni; possessing all of its class, glot; 'to have a tounge'
So, possessing all tounges, but in this case it is languages.
Also see omniglot.com
I cannot be an omniglot, it is humanly impossible.