All spoken and written languages - current or extinct - have things they express poorly or can't express at all. Art can be used to fill in the gaps of the inexpressible. How many languages would a person need to know to express everything, and by being able to express everything, would they be more capable or less capable of art?
But are there thoughts that language cannot express? I know many peoplewrite as if there were many thoughts, many valuable ones too, thatsimply can't be put into words. But are there any? Can anyone give mean example? Of course, many things can't be put into words — the cup ofcoffee I had this morning can't be (though the thought that I drank itcan). But is such an inability on language's part a failure to express something?