Oh yes, there *are* plenty of real words in there, not in every episode but - according to my impression - in more than half of them, one key word comes near the beginning as part of setting the basic scene, like when he starts to interact with an object - international words which everyone will recognise, like 'love', 'microphone' or 'umbrella', and the Italian numbers one to five for fingers as they appear one by one, and so on.
A fascinating link with the Italian and French traditions of mime. Another example of a (feature) film which doesn't depend on language and works internationally is Tage Danielsson's 'The Adventures of Picasso' - Swedish, but also distributed in America and Hungary at least: in the subtitles of the Hungarian DVD version each language is shown in a different colour, there are 10 of them including Latin, but you don't need to understand any of them to follow what's happening and how people are reacting.