This kind of question is now open to experimental investigation, with the use of TMS (transcranial magnetic stimulation) to selectively and temporarily interfere with specific brain areas, for instance the language modules. Here is one hit from a Google search.
With a little more time and effort than I have available right now it should be possible to turn up some interesting facts.
Before language, people must have thought without words. I often have the impression that I have a thought fully-formed in my head, yet I wait to listen to it unfold in words before moving on to the next thought. Perhaps I could think much faster if I weren't addicted to words.
Has anyone developed techniques for thinking without words?
This would have a little in common with Buddhist practices of emptying your mind, but wouldn't be the same thing. For one thing, Buddhists also try to empty their minds of images. More importantly, they are trying not to think, while I'm trying to think - just not unpack everything into words.