How much does language affect how you think?

A fascinating story called Life without numbers in a unique Amazon tribe on the Globe and Mail site boggles the mind. It talks about an Amazon tribe that has no concept of numbers, no words for colors, and many other cultural characteristics that most civilized people would plainly call "strange."

"Adult Piraha apparently can't learn to count or understand the concept of numbers or numerals, even when they asked anthropologists to teach them and have been given basic math lessons for months at a time.

...the Piraha are the only people known to have no distinct words for colours.

...They have no written language, and no collective memory going back more than two generations.

...They have no creation myths, tell no fictional stories and have no art. All of their pronouns appear to be borrowed from a neighbouring language.

...Linguists and anthropologists who have seen both the Everett and Gordon studies are flabbergasted by the tribe's strangeness, particularly since the Piraha have not lived in total isolation.

The tribe, which lives on a tributary river to the Amazon, has been in contact with other Brazilians for 200 years and regularly sells nuts to, and shares their women with, Brazilian traders who stop by."

The story raises the question of whether or not the inability to describe something prevents you from thinking about it. I think that's a very plausible theory.