I disagree. There have been many scientists, mathematicians, engineers, et cetera that have done amazing things, but they could only speak one language. These people have literally expanded how we think about the world/universe and created things that a hundred years ago people would have thought of as purely the stuff of fiction (if you go back 500 years it would be considered magic). So I don't think that you are necessarily limited by only your language skills.

This is a linguistically/philosphically based thought. Not a multilingual one. Even speaking one language is a wonderful ability. It is the idea that there are concepts, words and ideas that are not necessarily translatable. The way of thinking is, in a sense, set up like the structure of the language.

I agree.

You think with your language. There aren't any tools to think, at least not any tool as efficient as the language. 

So, if your language is limited, so is your world. You can't buy a cat from a pet shop unless you know what a cat is, and how to tell that you want a cat. You won't be able to go to Italy if you can't buy a ticket, and you buy a ticket to Italy by being aware of what a ticket is, where Italy is and how to get there. You become aware of stuff like that by thinking, and I think best way to do this is language.

This question comes into mind; How did the first men think? Images, probably. I'm not an expert. But their world was small, it was small enough to think without words. Their world expanded, and they invented languages. Be it a primitive one, or a complex one. 

The quote is true when you learn a new language. I'm a Turkish person. Without my English, I wouldn't be able to type these paragraphs out. Probably, I wouldn't be able to play games on computer as well! 

I think, the limits of your language determines limits of your world, both in real world and thinking. Think this, you don't know the words white and snow. How do you explain that it's snowing?

yes, if you mean the limits of one's own lingustic abilities and not of the language...:)

Language does not frame your thinking but also frame friends surrounding you.