I was reading 1984 by George Orwell recently, and one of the ideas was the creation of Newspeak. This was a form of language that limited the number of words available and reduced the possible meanings of words. The aim of this was to limit the scope of thought to "acceptable" ideas. You could not communicate the concept of freedom if there were no words to convey the idea. See the newspeakdictionary for more about this and the rest of the book.
Is it possible that your vocabulary or your use of language can limit what you think about? It would clearly have an effect on your ability to communicate your thoughts. How many times have you read something and said "I know that feeling but just didn't know how to express it"? So maybe that is evidence that language does not limit thought, only the communication of that thought.