I do think our thoughts are constrained by language - not necessarily by its unavailability, but definitely by societal norms that make it transgressive to say or think certain things. Even mentioning that certain thoughts you could say are transgressive makes you transgressive in a totalitarian culture. Thus a sign with 7 or 8 asterisks like gets people thrown in jail in Russia now. That's not because a dictat came from on high, it's because a system that coerces speech always attracts enforcers, who also raise their children to be enforcers; it is much harder to move from a system of repression to one of openness than the other way. Culture tends toward repression in every human lifespan to date except for one generation in the modern world, a few in the 18th and 19th centuries, and possibly a couple in ancient Rome and Greece. Civilization might tend toward open dialog in the very long run, but it's a much longer and slower climb, and setbacks - enforcement of language or "right" thinking - can be devastating and take thousands of years to correct.