Earlier quoted context omitted.
I tended to agree with the soft version. But I just realized, what it's saying is that you need to know about a concept. The language is not necessary. In theory you can imagine a concept, not give it a name, and still use it. You can't communicate it through, which severely limits it's use. And somehow I suspect that naming the concept makes it easier to manipulate, so perhaps that is a 'weak' version of the theory?
It also would not be propagated along with the culture, which is the hypothesis at its core: not that people of one given language are incapable of understanding some concepts, but rather that their cultural bagage tends to bias them and shape their way of thinking (which I would think is obviously true to anyone who’s ever lived in a foreign country or read literature or news articles in a foreign language).
Only dead languages are static, otherwise they can all adapt to new ideas as long as their sufficiently useful.